Relative reactivities of heteroaromatic cations towards reduction by 1,4-dihydronicotinamides

004DaOmm mpmlm

Trlrbe&m Vol. 42, No. 4. pp. 1007to 1019.1986 Rioted in Gut hth.

Rml8tlvm

of Hvtmromrovmtic

Re8ctlvltlmm

Cmtionm

tovmrdm

Rmdaatlon

am+ Ra

by

l,I-Dlhydronlcotlo88ldom

John

Dmp8rt8mot

U. Buotlng

8nd Judy

Chm81mtryr

of

Toronto,

L. Bolton

CJalvmrmlty

Ont8rlo

MS

(Received in USA

Ml,

28 May

Toronto,

of

C8n8d8

1985)

Klnmtlo data &t-e rmportod for thm lqulllbr8tlon of tbm l-nthylJ-altropyrldlnlu8 crtlon vlth Its pmmudobmmm (hydroxide 8dduct) and for the rmductlon of tbl$ obtlon by 1-bmnsy1-l,4-dlhydronlcotln88ldm. The C-2 hydroxldm addoat 18 the klnmtlc8lly aontrollmd product c8tlon 18 mlxmd vlth 8quooum bmmo, (pKR+ - 11.6) vhmn thlm pyrldtnlu8 thlm l~clmm romrrmngmm to the C-4 ldduat mm the hovovmr, thm thmr8odvn88la8llr 8orm lt8blm woduct
rmductlon

Slncm

qu8ntlt8tlvm

d&t8

c8tlonm

by

urn report

c8tlonm 88ny

the

orlgln81

hmm 8ttr8atmd rmductlon

the

(1.0. hrvo

for

lnvemtlg8tlonm pmmudob8me

ml80

hmtmro8ro88tic

nlcotln88ldm

bmliovod

to

hydrldm

donor

thm rmductlon

to

for88tlon)

bmcomm rv8118blm a8tlonm

roduotlon

ocaur

of

tovudm

a8n nov k

8mah8nlmtlc8Ily thm hydrldm

of

tha

of

l.l-dlhydroIn 1973,

vorkmrm2’1a.

In 8ddltlon,

88ny

the

of qu1nollnlu814.

of

8rm 8180

thm rmductlon

nov 8v8118blo.

of

Wo

nlcotinonltrllm

lnd harm nov obtmlnmd dmtm, vhich

l-bmnmyl-lr4-dlhydronlcotln8mldm17, klov,

by

lnd rmch8nlm8

of Slgmmn et 81.l

c8tlonm

klnmtlcm

thm klnotlcm

c8tlonm

obmmrv8tlonm

rmtmm of

upon

of

hmtoro8ro88tlc

c8tlonm

on the

reportmd

Cxtmnmlvm 8ddltlon

lnvomtlg8tlonm

l6 lnd phmn8nthrldlnlu810

lnlu81sJ

h8vm rmcmntly

recent nitrogen

8crldlnlum

of

lmoqu1nol

v8rloum

of

nlaotln8mldmm.

88ny

the

I-8ethyI-3-nltropyrldlnlu8

rmtem to

lnd lqalllbrl8

them.

v8rloum

rmamntly16r19. both

bydroxldm

a8lcul8tod.

1007

hydrorldm of

rol8tlvo

lon lddItIon

N8ny of

ton

hotmro8rontto rm8otlvitl*m lnd 1,4-dlhydro-

thorn@ reductlonm

v18 8 one ltmp hydride

8camptor10~11*1s*~0-2~.

for

almmmmm

Thum

c8tlon.

tr8nmf.r

In lovorml

from

8rm thm

cmmmm,

of

.OO Ltd.

J. W. BUNTING sod J. L. BOLTON

1008

lxperlsent81 speclss

8od

k8rlag

tr8nsltlon soch

st8ts

closely

p8r811.1

lnfluonced

seems

we fool

the

th8t

these

hrs

re8ctlvltlos conslder8tlons

hetoro8rom8tlc

the

r8ts-dstsrminlng

rol8tirs

thsrs

pseudobass

transfsr

and Lss**.

1s 8 close

fors8tlon

a sore

dlverso

cornl8tlons

corrsl8tlon squlllbriu~ However,

of

catlon36.

dlhydro AS dlscusssd


8qusous

the

8lcohollc

rsport

IhoT

8nd ths

sat

bs

to

9,10-dlhydro-IO-•sthyl8crldlne.

IO-sethyl8crldtnlus

la

hydrlds

would

substr8ts.

c8tlon

for

tor

re8ctlvltl~s

roductlon

by Krssvoy

c8tlons

for

th8t

th8t

not

of

rel8tlvo

should

const8nts.

rml8tlonshlps

for

s8ny

lxtr8pol8tlon

to

sosbers

dlmctly

may k

In

strongly

lsployed

solvsnt

systes

to

comp8rlsons

lsoqulnollnlus.

be

t8ken

cont&mln&ted

by

thwsodyn8slc

rs8ctlvltlas l lthar

hydroxide sadm

The 8v8118blllty

of

of

only

these of

of

cl8ssos

cl888

8crldlnius

and phen8nthrldlnlum

the

current

moch8nlsms

of

those

rel8tlvo

work.

8nd suggest

Into

d8t8

ro8ctlvltlos

1,4-dlhydronlcotln8mldm ro8ctlvltles

even

lxperlsont81

Sufflclent of

la

lon

extensive

two ro8ctlon

a p8rtlcul8r

difformt

th8t

s8ke

or

hrvlng

of

l,l-dlhydroslrll8r

llne8r

from

8110~8

lnterpol8tlon

though

such

energy

moskrs

are now 8v8118blo for

pyrldlnlus,

8nd s8y to

We present

such

future

consldor8tlons

of

should

t8ke

not

8110~

qulnOllnlUsr

crtions.

reductions

of

lnfluencos.

~188~0s

8ddltlon

ra8ctlons

for

cosp8rlson

comp8rlson

rol8tlvo

should

cars

k

8ccosslblo.

8 dot8ll.d

8re

tor8rds

reduction

lqulllbrlum

observsd

th8t

8s 8 sods1

strmsssd

c8tions

nlcotln8slde

such

the

hydrogen

ch8r8ctsr1s*20~21r23.

hstsro8ros8tlc

down for

effects

mlgr8tlng

studies.

Bern8sconlf4

bs

the

fro8

rlth

la lo

predict

lnrsstlg8tsd

brs8k

to

the

1,4-dlhydronlcotln8slds

qulnollnlum

tr8nsfsr

by solv8tlon

these

Thus,

of

to

dsnslty

‘hydrldlc’

for88tlon

const8nts

re8ctlng

klor.

rolrtlvo

of

h&s boon

bydrlds

hetorocycles

ln

v8rl8tlon

sat

corral8tlon

dotall

8nd

squlllbrtum

for

quits

8ddltlon

c8tlons

ths

k

polat

electron

on8 would

psoudobsss

8 llmltsd

constants thls

lon upon

of

hstsroaromtlc

bstwssn

to

rsductlons

hydroxlds

for

excess

8nd thus

nocIsophlllc

Ths us8

conslder8tlons

slgnlflc8nt

tor8rds

th8t

theoratlc81

8 the

these

conslder8tlon.


and

I-~tbTl-a-altrogFIdln1~~ bromids S-Nltropyrldlno t400 mg) 188 stir-d with sethyl bromide (9 ml> lo 8cetona solotlon (10 ml> in 8 pmssuro bottle untll proclplt8tion of the product ~8s The bromide 8 It “8s rscrystslllrsd ssrsr81 times from l th8nol. Pmr complete. 3H). 8.67 : c 4.80 (8, . , Klwt

lo 8tadl.s The roductlon of thm 1-methyl-3-nltropyr~d~nlum c8tlod by 1-knsyl1,4-dlhydronlcotln8rIdo 18s studlod la 202 CHgCN - 808 H 0, pH 7.0 (5 sN phosph8te buffor), lonlc strength 1.0
RcLtive ructivitiesof hemosronutic atioor

1009

lnlt18t.d by the lddltlon of a solution of the dlhydronlaotln8mlde In roetonltrllo to 8 temper8ture lqolllbratod solutlon of the I-sothyl-SnltroUndsr tbe uamnt reratlon aondltlws, the pyrldlnlos a&Ion la ‘aqsooas buffsr. loo of the C(d)-CCC) doobls bond of the dlhydronlaot1n8s1do is srtrswly :;::?s , and o8nnot ompsts sffeatlvsly with ths mora r8pld hflrlde tr8o8fsr reset Ion. The forutlon of l,4-dlhydro-l-meth~~-3-nltropyrldlne ~88 manltorsd by the Lacr.88. ln sbsorb8ncs st 400 ns on s Vsrlsn Csry 219 spectrophotoutsr In rm8atlons of the l-bsasyl-l,4-dlhydronlaot1n8slds (0.1 ml0 with 18rgs l xaessos of the I-sothyl-3-nltropyrldlnlum crtlon (1.0 - 5.0 mN>. All reactions proved to be klnstlc8lly pseudo-flrst-order In the reducing resgent, with the observed pseudo-first-order r8te constsnt being proportlon81 to the concentrstlon of the I-methyl-3-nltroplr1dlnlus utlon. The rstes of laulllbr8tlon of the 3-nltrovyrldlnlum c8tlon 8nd its pseudob8ses were n&wed on the Durrum-Gibson-itopped-flow spectrophotouter In solutlons 8queous solutloas
?ssrdobm8e forutlon by tbo The electronic dlspl8ys

8bsorptlon

8 pH-dependence

pKR+ -

ulth

x msx 400

of

of

vlclnlty

2 0.02

the

of

with

The

of

formstlon

Thls

of

thls

trsnslent

pyrldlno

systes.

spe~lo~,

In the

lntenslty

of

pH 10 end

lnare8slng

typlc81 sllors

10’ of

the

strength

k,b, the

8t

wlth

)

solution lts

pseudob8se

psoudobas. le8sured

dlsplsys

8t

pH 12.0,

end

the absorption

no slgnlficsnt

Is

complete

la

less

520 ns 8t

In the

rt

at pH 13.

0.1,

The klnetlc

of

squlvslont

The pH-dependenae

s pKe -

11.6

f

sonltored

In the

th8t

8r.

8lmost between

The sex 1sun quite

s~sll

8n estlnctlon

of

the

ssxlmus

sn scld

wlth

Its

conjug8te

0.1

thls

trsnslent

for

on the

lncre8se

13.

bolng to

zero

first-order

pH 11 -

r8nge

form8tlon

pH r8ng.. to



rt

coetflal.nt

8bsorb8nce bsse,

species

and
25OC). fe8tur.s

presented

8bove

for

c8tlon

-

8

slxlng the

close

8 twofold

18 pH-dependent,

of

to

convenlentll

sfter

the

studled.

const8nts

Thus,

v8lue

to

be klnotlcslly

in the

520 ns

to 8 const8nt

8re

8re

18 observed.

520 ns

In thls

decays

r8te

sac”

slmllsr

10 sllllseconds

to

13.

of

In 811 ~8808

c8tlon

spectrophotometer,

vlclnlty

t18.s

rhlch

proved

pH 10 -

+ 0.4

stopped-flow

subsequently

thst of the lqulllbr8tlon l vslu8tlon

la

th8n

r8t.s

decsy

r8nge

sbsorbsnc.

1-methyl-3-nltropyrldlnlum

131 In the

pseudo-flrst-ardor

= 6.5

W’lcm-l

the

In most ~88.8.

Thls rlth

11,

I

species

r8velength

pH 10 8nd

1.2

8queous

thls

x IO4 H”cs’*

maximum la the

sbsorptlon

absorptlon

pH-independent

of

2S°C).

cont8ln

of


18 complete

at thls

stopped-flow

solutlons

lnstruseat

tr8nslent

absorbance

la

l,4-dlh~dro-3-nltropyrldlnes27.

solutions

buffors rlth

in our

thls

0.1,

by

c8tlon

lqulllbr8tlon

its

2.0

dlspl8yed

rqueous

s~cles

desd-tlse

coefflclent

thls

astlon

500 ns.

8queous

trsnsient

with

strength

lqulllbrsted

these

When neutr81 slxed

(lonlc

spectr8

of

spectrus

consistent

nm
18 typic81 spectrs

9.42

I-methyl-3-oltropyrldlnlum

pseudob8se

lqulllbrstlon

1s

J. W. BUNIINO 8Dd J. L.

1010 for

the

for

~rrvlously

olomrly

C-S

substltatmd

o8tlon8

qoinollolum

bearing

domoa8tr8ted

favor8

addact.

C-4

the

OUrIWnt

th

8tOdf

psoudobasa

tormtloo

QyridlOlUm

C&ioOr

vlclnlty

09

500

although adduct,

8 8Q@ClO8

the

of the

of

.vmlumtionlg over

C-4

t0 that

oacur8.

th18

9K2~+ = 11.6 and pK’R+

the

Sub8aqUeot

88118118

to k

lquillbriam

the

rOQOrtOd

18O:l)

(1.0.

1-methyl-3-nltroqulaoltalum

9.42

l

the

ratio

18

l

w8relrngtb

la Schero

l

of

t0

8hort.r

r~8pectIv~1y.

th18

for

CbW8Ot8ri8blO

of 98eudobm8e8

rmtlo

C-2 Q8OudOba80 8pocle8.

the

Qr~lOU8ly

* plC’R+ -

in

18 th8

i808orlXmtiOn

18 dot8ll.d

8ltUmtlOn

tWQOrt*d

I-•otbyl-3-nitro-

8n ab8orQtlOO

derlV8tive82'.

lb8orptloo maximum then ldontlty

tha

18 known

18

OOntrOllad

more 8t8blo C-4 hydroxlda adduct hmvlng

thormodyommlc8lly

of

bVlng

of

&on

pudoban

ObWrVatiOO8

ion lttaok 8t C-2

It hm8

fex%mtLoa

dablo

mor8

kinotic8lly

an lb8orptlon urlmam

Suoh

08.

of p8audobaw

cootrol

a 818llU

Ior

C-3 8ufmtltoent,

thormodynamioally

with

&8crlkb

to tho88

oatlon81gD2*.

8QOatrOQhOtODOtrio

by hydroxide

I,?-dlhydro-3-oltropyrlddno

l llou

klnetio the

COO818tant

t0 glV0

l lmllmr

very

lloctroa-rithdraviag

8topQod-flow

are

are

1-~oth~lqoIoollnloa

m

that

thm C-2 bydrosld8

the

cmn

catioo

1-methyl-3-nltropyridiolum

BOLTON

1, and

ve

th.8.

data

13011

In favor

8

l88Ontlally

idontlcml

C-4 and C-2 hydroxide 8dduct8

cmtionLge2*.

2 9x 'OH 7

a ,

R+

"02

f

I no

k

t-OH1

R+ I NO Tho

for tha


kob8

= kCH

1600

N"8"

abovm for the Q8OUdO-fir8t-Order

18omerlr8tlon

to that

pH-lndapandeot

the

da8crikd

pH-depandenoo

reQOrtOd k,b

18 the

for

for

~motloo The

at

8wond-order

09

ti8e

hydroxide

the

C-2

ton

pH

rmte

from

to the

Qroee88

#lbarO I(" 18 the

1-methyl-3-nitropyrldlnlam

ljactlon

the

th18

8 ml

= 6.5

]4r / f2R+

of

of

the

QrOdUCt for

Catloll,

and

the

p8oudob880.

C-4

lloatronlo

hydroxide

qUlnOllnlUm

18 rolatad

con8tmnt

I-wtbyl-8-nltrogyrl4lolmm

dependmnco

ln the

11 - 13 1OnlC

C-4

k-OH

Of

ldduct

hydroxide = 0.042

8-l

COO8t8nt8

18 ml80 tho

Cat10n81g82a.

to )bH

Wat@r.

r8tO

of Schema 1 by thU8,

kc,H -

ion mttmck for

the

at

C-4

8pont8neOu8

a&ion

lb8orption 8pmatrom of a 8olutlon

of

Rehtin mctivitks of hctcrosromrticatioos coatainlng

an

lqulmoLar

mixture

l-~oth7l-S-nttrop~ldInl~8 at nou

358 a8 dw

to

lb8orptlon

produc8d

during

vlth

8poctrua

the

no

S-nltropyrldlno 435

at 496 IID.

8lgnlfla8nt

oi

thi8

report8d

for

l

aad

cororkw827.

8o~utlon,

1,2-dlhydro

18om8r whlcb

9500 n-lo.”

> In 8p8atru8

pUrpO888.

Hor8ver

It

oi

ln

8hould

al80

-

888ignlng

b8

not8d

that

catlon8

hrva

10 frvor

8p8cl.8

tha

A

uMbl8

to

l-t8

botweon di8CU888d

deflnltlvoly

th8

8boVO

re8ctlon8 8Cd

of

bmlor,

C-S

88

18om8r.

r8ductlOn

ld8ntlfled

it8

compw8tlve

1.4-dlhydro

the

88

of

Ul

for

1,4-dlhydronicotln8mlda

kon

8aS

-

l.C-dlhydro-S-nltropyrldlne

product

18

8p8ctrum

Cextlnatlon ao8filclent

C8tiOn8

8

18 COn818t8nt

dl8pl8l8

fro8

8lmllulty

of

08

at -5

8pWtrU8

8p8C188

b88n

l~xl~o~

I,4-dlhydro-I-methyl-

dliferent

h8V8

nductlon

th8

of

fh18

bh

CJUinOliniUR

thl8

POlLIt

prOdUd

8r8plo

520 nm

of thm alo8a

ad

ln

3-c~mnop~rldlnlmm

Am..

8Uth8ntla

vlov

m.

qulto

18

tlao

or 8117 lntorwdlrt8

n ruthontlc

8nd

l ltb

tha

lbaorptlon

Tba

1808b8tlC

r8RCtlOn.

8olutlon.

8n

pyrldlnlam

contld8nt

h88

rthmnollc

8b8OrptlOn

f881

C18Wi

ConC8ntr8tlOn

by Severin

8uktltutmd

m

wsd

1.

d8area888

tkm cow88

In 8othanollc

08

ln ?lgun

1,4-dlhydronlcotlo~m1d8

uslmum

that

I-knzll-1,4-dlhydronlaotIu~l~ 18 shorn

cmtlon

th8

lndlcatos

ai

101I

product8

88 the

of

3-cy8no-

t,4-dlhfdrop~rldlno817.

WAVELENGTH

lm Tlw

d8gmnd8na8

oi thm ab8orptlolr l-rthyl-S-alt~tdloium

lirtw8$

1,44th*ala8tla881dm Um a.0 CRC13 md 8t

r80Old8d

lndlomtd Th8

r8t8

kln8tl~lly 8pOaie8

tlU8

on 8ti

Oi

tir8t-odor

18

plr88llt

8p8atrum.

with

ill

lo

of

8p8atrum

8it8r

illitl8tiOn

ti8OrbUl~

ill

th8

Oi

VlCllllty

1,4-d1h~dron1aotln&mlk

20 -

ut

8qulBolu

broil& and I-basylin tol motonItrll8 - 80% u8tor, 25%
<8lBUt88)

ilMX.888

(nm)

I

100 iold

l

xae8888

ior

of

th8

tiW

Of

pH

Cl.0

lI>

7,

10010

Spoatr8

r88atiOlr

uw

U

440 nm 18 C188li1l

r88atlon8

la

rhlah

l-m8th~l-3-nltrop~ldlnium

thl8

1012

08t

J. W. Bm-rmo

ion.

Pwodo-flrat-order

of tbl8

pyrldinlrm

COn8taflt pH 7.0, 0.95

c&Ion

8nd

f

M”8”

= 0.72

k2

lOnl0

,+ 0.04

rate

0.06

8tr8ngth

R"8"

nlCOtln8eld.

th18

88

the

the

l vrlurtlon

of

for tbl8 reduction 20°C.

Onhr

re8OtiOn

U8lng

8nd

reductant,

thu8

to the oonaoatra8Lon

proportional

oon8t8ot8 arm

allow

1.0 8nd

iOr

md J. L. 6OLlKBN

th888

sooond-order

the

In 2ot

CH@l

8t

- 802 H+J k2

condktion8,

88n

rata

=

4,4dlbut8rlo-1,4-dlhydro-

k2H/k2D

2.0

-

k 0.3.

DIWWSIQ Hydroxlda

Ioa Witloo

&t.n8lVO

lln88r

8Ub8tltUent

8ddltion

fEW.

l ffeot8

upon

both

to qulno11nlum1g~2g

8eoond-order

r8t.

r8te

COn8t8nt8

for

c&tlon8,

th.

rhlle

for

8

for

t0

8pprOprl8t.

tim.

of

heterO8rOm8tlC

CltrOgen

by

reduction

the88

hrvlng

the

re8otlon8 8.rl.8,

th18

point

pKR+

r8t.

8tUdi.8

of

18 the

p8eUdObm8.

8t

log

koH

the

1-knZy1-

lqulllbrlam

8nd

Thll,

mbove.

Of th.8.

th.8.

r8t.

d8t8

8.e~

V8rlOU8

8n

01888.8 ld

lon rddltlon

Of

rO18

8re

hydroxide

loo

8ddltlon

8N

8V8il8bl.

for

..&.r8

hydroxld8

.8oh

8.ri.e

8t

COmp8rl8On8 by

c8tlon

8Om.

8t pKR+ the

tW2ent

by

811

require

cho8en 9 10.0,

8lnC.

lo-8ethy18orldlnluB

klnetlo

reference 8nd

8nd

8Ub8tltUent

for both

Of

lOn 8lmp1y

18 8 oonvenlent

ln l8ny

8V8118bl.

r.8OtlOn8

for

1,4-dlhydronlcotln881de81m13,

d8t8

08tlOn8

the

fOrm8tlOn

Thl8

heterocycllc

OOn8t8nt8

tOVrrd8

unoo8pllo8ted

08tlOn.

r8te

m8y

8nd

C-l

of

Th.8.

~81~08

pl(~+

+ 8.3

- -0.36

~KR+

+ 6.84

8ttrok

occur8

l8oqulnollnium from

= -0.46

ion


COn8t8nt8

be l 8tim8t.d

r.8p.0tlV.1T1g*2g.

Hydrorlde

V81U.8

to m8k.

25’c3’.

fro8

qu8ntit8tlV.

o8tlon8

= 10.0,

km

for

8180

effect8

reduction

mech8nl8tic furthermore 8t

C-9,

for

8nd

fOrm8tlOn.

qulnollnlum

log

Cor

p88UdOb88.

8 OOntr81

tr8n8f.r

Second-order

pKR+

8OlUtlOn

8orldlnlur

Of

8 8.mb.r

cho8.n

for

hydride

l 8ten8lv.

rhlch

U@h8Ve

pl8y.d

pKR+

for

observed

h88

It

On17

ton

phenanthrldlnlu8

hydroxide

Of

rO8OtiVitie8

OOn8t8nt8

V8lUO.

V81UO

8inCe

both

COn8t8nt824.

intrin8k

in 8qU.OU8

-tlOn

r8tO

r.8OtlVltl.8

008wrl8On8

fOrm8tlOn),

rOl8tiVO

18 the

by

pre8ent.d

r.80tlVlti.8

r.qUlr.8

lqulllbrlu8

Of

COn8t8nt

8re

8nd

8re

tOW8rd8

lntrln8lC

re8gent8,


OO~p8ri8Ofl8

c8tlOa8

8cridlnlU8

r.18tlV.

c8tlon8

the

Of

888.

8nd

the

8nd

catlon8,

there

iOr

for hydroxide

d8t8

th.8.

08tlon

8V8118b1.

1,4-dlhydroniootln8mlde8.

COmp8rl8On8 tOW8rd8

Of

pyrldlnlum

oon8ld.r

of

8ddltlon,

r.8OtlOn8

n0W

lqulllbrlum

reduction In

8n8lOgOU8

d8t8

8nd

8r.

180qulnollnlum2g

8nd

l,4-dlhydronloot1n8m1de14*1s. 8V8ilrbl.

lul8tiOn8hip8

.n.wt

8t

the

hydroslde

in T8b10

8tt8Ck

l8ch

Oltlon8,

re18tlon8hlp8

81‘. g1V.n

lon

la

8t C-4

of

dl8pl8ylng

lquatlon8

(11

8nd

l21,

1. 111 I21

C-6

of

phermnthrldlnlu8

08tlon851,

8lthough

them

ReLtive raaivitia of betamronmtic atiom do not

appear

be aay

Hmror

c8tlons. 8 series

of

qUinOlikliU8

two

th.

c8n

be coosldend

CIS.,

koH -

3.4

sP99ests 1s 1.

pKR+

t 10.03

of

c8tlon

thls

fh.

h8ve

8

to

C-l

la

121 8nd

131

of

s.rl.8

121 glV.S

.CJU8tiOCh

pl(R+ = 10.0. 8t

C-2

re8son8bl.

8pplic8tlon Ue

ln

lOn 8tt8Ok

x IO5 Nmls”.

upon tbes.

lqulv8lent

8s

Of

hydrorlde

thrt

8tt8ck

8S c-2

8~liU8tiOfl

8OOept8bl..

in Table

loa

01th~

or 8lt.m8tlv.lv

13323 iOr

C8tlOnS

109 kCH 9 -0.43

hvdroxlda

of

phOn8nthrldlnlU8

8

gives v81u.s

v8lu.s

rates

fOr8.r

lqu8tlon

c8tlons

these

two

slte

for

uslog

of

c8t1ons

Ilrr

t0 phen8nthrldlnlua these

C-6

1 10b R’ls’l

qulnollnlu8

reports

laoqulnollolo8

Alt.rn8tlv.ly,

between

thls

08tiODS.

= 1.7

)bH

to

1013

Of

89ree8ent

lqu8tions

of

chosen to use the 8e8n of

131

T-1 R.8ctivltl.s

of

Hydrorlde

HeterO8rO88tla Ion

8od

C8tiOnS

Of pKR+ *

10.0

tOw8rdS

1-Renryl-lr4-d1hydroniuotln88lde

_________________~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C8t Ion

‘bH8

‘Zb

Rel.

k2’kOH

k2’kCH

~~~~~~~~~~~~~~~~~~~~~~~~~i--~~~~~~-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Acrldinlu8

ssoc

gulnollnlu8

(C-41

Pyrldinlu8

5000

(C-41

Qulaollnlu8

rood 80

000

(C-21

0.73 0.016

0.3

3400

3.8x10’4

(8.

3.41105

1 .6x10s

80

<2x10-5


Phen8nthrldlnlun

2.51105

0.8

3.2~10’~

0.7

Isoqulnol

1.71105

0.3

4.7x10-6

1.0

lnlua

____________________~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 8Second-order c81cu18ted

r8te

const8nt

8s described

bSecomd-order

r8te


In text

const8nt

Unless



I-benzyl-1,4-dlhydronlcotln88lde strength

reference

(301.

aPro

reference

(131.

since the

ion

lndic8t.d for

In

c81cu18t.d

Wrom

‘Not

re8dlly no

8ccesslble.

2OI CH3CN ln

8tt8Cks

otherrlse.

reduction

8S d.SCrlkd

8uch

but

l,P-dlhydroqulnollne

re8ctlon

Of 8tt8Ok

The

23’8

hydroxide

by 808 H20,

text

lonlc

unless

otherwlse.

indlC8t.d

work

1.0,

for

8t

me h8ve

C-2

thm

I-methyl-3aItrupyrldlnlu8

h88 pKR+ = 9.42

for

p.Oubob8.0

th8n

1s observ8ble

products14S 8S 1.8s

s8811.r

108

a8tlon fOlr8tiOll

for 8tt8Ck

la

the

conserv8tlvely Of

tb

thrt

r8t.

hrs 8t

C-4,

p8r

8t

speotr8

lstinted Of

been

8tt8Ck

studled

which

C-4

the 8t

r8t.e

C-4.

In the

tS quit.

of

current

0108.

t0

1014

J. W. Wnmwo

pKR+

10.0 rhlcrh

-

ths

81Op’S

we have

th.

Of

log kf,,, “.

qulnollnluB

c8t1oas

1600

rsported

H-‘8”

8qU8tlOC

141

eqU8tlOn

then

log

km

for

kdaotlo8

of

CloOtin88ldS8,

fro8

ths

raotlon

Of

8s

to

thS for

donor

BH (1.0.

niootln88lds

Of

8 SOrleS

the

~KR+

Of

811

of

lqustlons

for

ion

B+

AOH

+

B+

KoH

A+

h8vlng

r8tS

to

the

of

k2

lqu81 loo

pl(R+

by =

KH Squlllbrlus

by

lqU8tlOtlS

~81~08

listed

in

of

8nd

T8blc

181, 1 for

c71

log

k2

=

-0.50

pKR+

+

I81

of

rS4uotlon

4.9

h8ve

roportsd

o8tlon

of

the

rlth

8

seriss

simply

k

ohosSn

should

8pprOIlB8tS

8

qulnollniuS

<8t

C-4)

to

rS18t.d

rrSprctlV.ly14r16. qalroIlnlu8

8nd

~KR+ = 10.0.

+ 7.9

81x04

KoH =

8 oonst8nt

8rw

pKR+

r8t.w

for

log

OOnSt8ntS.

-0.56

5-sethylphen8nthrldlnluS

8nd

I-bmsyl-1,4-dlhydro-

-

8I.l’

C51

vlrtu81

KH S8y

10.0

mduotlon

171

Squ8tlon

lsoqulnollnlu8,

h8Vlng

for

oonSt8nts

In

the

Yor

KH.

k,

St

B+

it

I61

log

roduct

l-bonryl-

prlnclpls,

rS8otlng

h8vlng


8nd

l-bonS~l-l,4-dlhy4ronlcotln8sl4s

C8tlOnS

prodlct 08tlOQS

si8tl8r

const8nts by

the88

811

USlng

tAOHltB+I/[A+ItBOHI~

=

rS8ctlons

C8tlOnS

squlllbrls8

In

qulnollnlus,

ths

8888

lqulllbrlus

the

log

rates

PKR+ = 10.0.

1,4-dlhydro-

In

tr8asfsr

+

ThSnfon

c8tloos

V8lUeS

-

gsner8to

by

speoios.

AH

A+
pl(~+.

second-or4Sr

lsoqulno1lnlus

2-propmol

to

This

oosp8rlsons

o8tlons

8pproSls8tloc

8Crldl8lUs>,

Sq98l

8nd

donor

ths

I-knzyl-1,4-4lhy4ronlootln8sl4S)

Of

re8OtlOns

s8k8

sStls8tss

8nd

8 0108e

C8tlOcS 8n4

08tlOnS

Rokrts

8n4

-

of

C8tlon

rsduotlon

to

hydroxldo

tAHIIB+lIIA+I[BHI b8

8bh

hstsrooyollo

r

should

lsoqulnollnluS

r,

c8tlons.

h8ving

hydrl48

KOH BoH

phsn8nthrl4lnlus

Those

us.

c8tlon

8 p~rl4lnlus

rmotlons

8n

.

pKAR+

The

~88

pfildlnlus

towads

of

KH ,

BH

KH =

of

us

p~rldlIbiUm

th8t

141

rs8son8bIs

Obt81n

161.

hOtSrO8rOS8tiC

SOrimS

Cl]>,

of

c-4

for

n-*8’*

Us

ktSSon

sqmtlon

+

frOS

8t

8 oonst8nt

la

Thus,

fdr

sl8l18r

1-•thyl-S-nltropyrldlnlus

rS8ctlvltlSs

oonst8nts

A+

hydrlds

= 800

Squlllbrlus

+

-

8ttrck

tr8nsfsr.

tr8nsfsr

A+

PK’R+

lon

lqU8tiOn

in

co8p8rlson

hydride

posslblo

hydrldo

the

lntrlnslo

1,4-dlhy4ronlootln8Slde

for

for

l8

On the a8sumptioa

+ 7.5

rsqulrss for

bs

rSl8tlonshlp 8s

koH

pale.

1-~n~l-lr44l(rtbroolwtl~81~

CoSp8rlson

should

a nfermoa

-0.46

hydroxlds

pKR+

as

ME+

8bovS

-0.46

br

oonst8at.s

Cl...

prSdiOt8

*

chossn

Sad J. L. BoLToN

solvent

by 8t

r8ts

const8nts

for

rsductlon

l,4-dlhy4ronlcotln8ml4e 25OC.

lo-sSthy18Orldlnlus

th.88 8nd

d8t8

of

krlv8tlVeS lfldlm.

th

5-8sthylpln88athrl4lnlu8

th in

X’S18tlVO

4:l

Rclrtiverrscf+i&v of llcwouorns~

oatlon8 ths

by tha

.A-

1,4-dlh~droalcotln8mlds

IO-uth~luw1dlnlu8

l8tlnte

o&lon

k2 -

cstlon

by

0.0.

lgrvornt

for It

lqustlon to tot

C-4

tha

2W

for

the

mdoctlon

rlth

lm8oud for

the

lf”8-’

of

8 s

for

tha

vslue

for

Is

of

the

upon for

ttn

rat8

thI8

deg8aerat8

snd

Relatlva

of

cstlonr

touarda

attack

of

OOn8tant

rolstlve

both

rat.8 rlth

Im slso

191 osn

k2 -

be uloulstod for

pKm+ -

the

of

lstlutlon

the of

sppllosblo

abovo

reported

k2 -

10.0.


7 x 10e4 lf’18-1

of

system.

reported

k2 =

I-kaxyl-

catlon

solvent

of

predlot

to

ktuem

8 vsluo

This

75% H20

at 40°C,

<2.7:1>

for

st

uo

ws8 baud

sod

CrlerJ2

sad

roautloa

l-kns~1-l,4-dlhy4roolootInsmldr syrtom

rhloh

s8tlmstm

by vmn Elkoron

nduotlon

lolvont

at

C-4

of

than

our of

undsr

th8 those

2b°C.

4erlvrtlve8,

8t

C-l

klmotjc

pyrldlnlum

oentrol catIon.

of

dorlvad thsn

the

rstes

phenomenon of

oven

the

ola88a8

of

of

8orld1nla8

C-2

of

qulnollalum

r@te8

C-2

thormod~nsmlcslly

of

Ion sddltlon

of

Ion

ortloa8

are

ostlons

forutkon

or

of

sro

1.4-dlhydrop~rldlna

demon8trrtod

at

hldroxldo

C-9

that

of

of

reduotlon

rste8

8ugge8t

formstlon

form&Ion

tho88

the

upon hydrorlde

18 forthor

pmoodobm8e though

of

8t

catloos,

818ta88

ring

thst and

Tthmmmdata

8 serle8

1,4-dih7dronIootlnssIde

obvlou8

Imoq~LnolIalum

of

r8sctlvlIlo8

snd

qulnollnlum

cmtlonm.

this

latrlnslc sttsck

pyrldlnlrm-and

f88ter sod

the

v8lue.

1 for

In tsblo

con8t8ot8.8888arixed

1s Lm8edtatol~

pban~thrldlnlum

lntrln8lcslly

rste

hydroxide-ion

It

1,2-dlhfdrop~ridiao

the

In

It

In 258 CI$,CY -

oun 8tsndsrd

~KR+

osloulstod.

muoh llouur C-6

pKR+ oornlat1on

cstloa

tr8n8fer

W’181n’1

trsnafor

the second-order

crtlons

k

our

a8 an prodlct

8110~8

may use

rlth

In our

o8tIoa

la

(81

Rmotlvltlo~

Fro,

am

I8 tromtmd

oattons

I-knr~lnlootlnsmlde

0.119

-

hwldo

I-moth~lnlootlnonltrllo oondttlons

lqustloa

us

t91,

rerctlon

8oaoerod

88tlmrt8

This

181 to

umlng the dsta

sgroonat

k2

uo

from lqustlon

lqustlon

than

hydrldo

th

rossonsble

oonmtmnt

lxporlwntslly

equrtlon

degenerste

for thi8

8y8t8813,

lqustlon

k2 v.

s pTrldlnlum

of

thm

sy8tmm.

lt.9431) use

log

cstlon8,

Tbl8

of

pl(R+ = 10.0.

the

ostlons

for

favor

(91

md

la

have emtinted

8olvent

at C-4 of qulnollnlum

rsductlon

1,4-dlhydronlcotl~ldo This

of

o&Ion.

tat

!I-“-’

of

la

CI-•sth~lphsamnthridlnlum

latlmatod

Nw18-’

confldontly

pyrldlnlu8

C-4

the


aatlon

400 N”8”

l

~KR+ + 5.1

a furthor

10’4

uo csn

pyrldlnlum

of

k2 0 -0.96

b

c8tlon

roduotlon

redaotloa

reduction

lo9

of

O.Obl)

l

SOOOrl

to b

80% H20 8olvent

In our

tha slope

that

1-methyl-3-nltropyrldInIum 0.9

k2

m pb*n8nthrldlnlum

18

(71

ttn

CHgCY -

our

Thus

cstlon.

n-1,” If

and k2

ratlo,

la

5-moth~lphwanthrldlnIus

l8oqulnollnlu8 0.2

Y-*,-l

thlo

d.rIvstIro

I-Innsyl-1.4-dlbydronlootlnamlds

18 In lxomllont WhOn ths

Uslog

dartvrtlvo.

scrldlne

lOi5

ations

of

lo

ttm mom

the

current

uork

by

I-methyl-S-nltro8tablo

psmudobmmo

18

J. W. F~JMTNO and J. L.

1016

hydroxi&

rho C-4

On the

ldduot .

other

than

for

boon

lhom14*s3

that

occurs

rmductlon

such

work>).

qulaollnlua

oatlonm

the

aaae

In general.

all

thlm

that

the

true

<3-CM”

and

each

for

3+02

cat1011

the lorldlnlua,

draaatlmlly

relative

to

lnhwkcmd

the

k2/bH

1.2-dihydropyrldlne

Noontl~

qufnollniua

of

18 alao

Interemtlngly,

for

utLon8

8180


display

type

for

mymream

lmoqulnollnlum

l

C-2 of to

l eemm

and

nuclmophlllc,

We have

the

algratlng

the


catlonm

In Table

1 should

nlcotlnaalds

It

reduction

one l lght be at

of

learnt

dlhydronlootlnaalde qulnollnlum rlth state

aechanlma

more

formation

of


a l laple for

taclle

all

and

than

simple

1,4-dlhydropyrldlne

oatlons

attack

la thlm

are

lo the

transfer

derlvatlvem

bat

not

umrm

and

of

thorn rate-

p]rrldlniUa

the

catlons

l,l-dlhydro-

lo Table

enhanced

1 for

thum apparently

rate-deteralnlng theme

data

18 lvallablm

for

Rather,

Table.

hydride

and


observed

of

transltlon

lpmoles

both

and

reduction

The draaatloally

ars

pyrldlnlum

catlon

‘bydrldlo’,

for

upon

81mllar

a

reaotlvltles

Ion lttaok. thaf

of

via

aaaely

attaok

the

‘hydrldlo’

by

llallar

nocleophllio catlonm

18 quite

relative

qnalltatlvely

rsdactlon

obmervatlon

qulnollnlum

the

lon

proceeds

lcrldlnlua,

nucleophlllc

lhomn that

lttaokm

lxpmot that

tow&m

upon an lorldlnlua

recently1s*16

slallar

and hydrorlde

redaotlon

lnconmlmtent

by the

hydrogen

lntrlnmlo

of tha

hydroxide

for

attack

lon

theme

of

much an lmmuap~lon.

lgalnmt

by l,I-dlhydron1cotlnaaldms

In character. for

oatlona

18 allayed

hydrOXl&

reactlvltlem

reprementatlre

etteotm

molvatlon

for

lo rhloh

lpmolem

lrguaent

catlonm,

of

cations

relative

the

of heteroaroaatlc

catIonto.

lsoqulnollalum

that

mmuae

lon ~111 be reamonably

lctlvatlon

of

lorldlnlum,

and

lndlcatem

catlona.

The ltrongemt

clammes

lmoqulnollnlua

tranmltlon

to

of different

varioum

of

C-2,

reaotivltlea

ratio

has

rmdmctlon

reduotlon

of

It

p~rldlnlum catlonm

catlonm

mm thlm

hydrorlds

pO88lbllity

rates

catloam.

at

Ion attaok.

toraatlon

for

of thmme olammem

deteralnlng

than

rmlatlvo

of

reamonable

rmaotlvltlem

mtate

C-4

lcrldlntua

and

8y8Cma8.

towards

lntroplem


of C-3 lubmtltoted

aagnltude

meemm

oatlonm

an

at

1,4-dlhydroalootinaalde

phenantbrldlnlua

theme

imoqmlnollnlua

and phenanthrldlnlua

qUinOliniU8

lttmok

and

and hydroxlda

for

lmoqulnollnlu8

It

qminollalua


reaotlvltlem

I-benryl-l,l-dlhydro-

bl

for

rapldly

norm

Coaparlmoa

reduotlon

toward8

reduotion

ot

I-beamyl-1,4-dlhydronlootlnaalde

two olaammm

of


bm of

r&mm

thw

tbm phenantbrldlnloa

cation8

the

hand

arm muoh gnmtmr

nlcotlnaaldm

BOLTON

for

Imply

that

the

1,2-dihydropyrldlne

derlvatlves. Conslmtent seohanlma lnd either

for

rlth reductloo

theme of

ldeam,

ue have

lcrldlnlua

l- + H- or l- + H+ + l- for

recently

aatlonm

redactloo

argued

for

la predominantly of

qulnollnlom

an l- + H' aqueous

l4 and

aedla13~

l

ructivitica ofhctcroanmaticatiom

Relative p,rldlnl~.~’ mast

oatlons.

the

expected the

thls

series

nstched

knzyllc 8s

C-3

8180 be noted

reduction substltutod

r8nge

tb8n 8re

the

believed

p8rtly

for

C-4

fros

pKR+ r8lues

mtudles

2.0

8bove

the

of

88W

rmsctlon

rhlch

const8nt

for

SyStSSSsesbers

the

c8tloas

of

rhlch

8re

the

re8ctlon

8nd thus

8sount the

this

side

of

the

thti

to rel8tlvely

lqulllbrlus

Roberts

IO-sethyl8crldlnlus r

oonst8nts

differ

these

trloyclic

10 uklrw

et

resctlon

th8t

the 8re

such

reductions lor

Them. being

when

lvslasted

xH -

[Sl,

for

vi8

cases

I

d8t8

p81r21.

ln which

lOi

for

the

are

the

subject

8d8itt.d

k the

18dd.r

different

for

lppro8chwd

procedwe 8ust

b8ok

lter8tlve

8n

re8ctsnt

lt

s8me 18rge procedures*.

reurtlon

of

I-setbyl-1,4-dlhydro-W-knsylnlaotla8slde

of th8n

1.0.

4 r

lo6

by whlcb

lspectmd

on the

10<11.g4-10.0) it

should

be kept

= 100 ln

ortlon

rltb

thls

lqulllbrIus

tlnso

b8sls

the 81~9

tba 6-netbylphonmthrld1nlu8

of

8

rmte

the

18

this

For

8v8118ble

lqulllbrlus

by

hydride

tbe

conmt8nt

8lthougb

4.4

the

8180

(!!110*21r22*36.

lv8lu8ted

fsvored

their

recently

spectrophoto8etrlc

occurs

by Breslor

of

some of

1s re8dlly r8te

used

b8ve

for

COnSt8ntS

brsls

lqu8tlon

then

In sever81

quote

th8t

There

process

by two soserh8t

factor

such cosp8rlsons

for

tr8nsf.r

the

form

of

uncmrt8lntles,

with

o8tionst

8re

lqulllbrlua

to

lqu8tloa

side

of

aonst8nts

18rg.r

of

3-M0214)

processes.

of

vslues

by

one

constsnt

s1.l’

for

effects

electron

8clds.

8v8118ble.

lstlnsted

This

18 frr

that

Ir,

f8vored

tbm resctloo

8gent.

c8rbon

of

1s reported

artlon

106 for

reducing

two

1s

rlth

cycles

represented

lxperl8ent81

coostrnt

tr8nsfer

18 slmll8r

thersodyn88lc8lly

8groewnt

p8rtIcul8r.

1.1

fl~l

previously

1.5

3-W;

reduction

more re8ctlve

Isotope

lstls8tlon

the

tlse-dependence

equlllbrlos

18rge

lspresslve

8re

aoastmt

bsck

hydride

8e8sure

In fsvor

the

thls

la

resk

lqulllbrlus

the

flttlng of

Ue feel

rrte

r8lues

and the

for

the

reported11B1s*20r22

formation

theraodyn8mlc8lly

Ylth

for

t8k.n

very

thst

6.6

for

c8s.s.

dlrmctly

11~8 he8vlly

directly.

procedure

to

-

the

klnetlo

consistent

thersOdyn8810 of

(1.8

These

4.4

8re

to

<1.S613)

c8tlons

pseudobsse

8cldlthm

rttespts

s08e

we h8ve

reported

1s slml18r

one-step

these

In the

lquillbr8tlons

l 8se

kZH/kZD -

-

reduction

for

tr8nsf.r

%I-

for

udla.

k2”/kZD

lo

th8t

8nd cororkers54*3s

In

to

re8ctlvltles

ortlon

be genuine

r8te-dmterslnlng The rppro8ch

th8t

th8t

re8ctlon of

to

effects

lsotope

fros

bUdi

lntrlnslo

1-8ethylqulnollnlus

ss8ller

sr8ll

la

of rjth

conslsteat

8vallsble

lo-sethyl8orldlnlum

the

of

rqueous

been

amps,

re8ctlvltlos

1 uo

lntermedl8tes

st8blllz8tlon

trmsier

rel8tlvs

In Tab18

r8dlc81

r8dlc81

lnore8slng

ln predomlluntly

I?

ths

obaorrod

of

l-methyl-S-nltropyrldlnlum for

which

one electron

latemdlstes.

stabllltlss

rppe8rs

should

the

the

rdlcal

> pyrldlnlsm

rol8tlvo

lncre8slng

1n*olvlag

nch8nls88,

therrodyn8mlc8lly.

It

found

VI8

> qrlnollnlos

Thus

of

pr0088a

of co*rse

8crldlnlum

Suob

1017

of

the

pKg+

v81aes

for

only

used

.

slnd

th8t

se

h8ve

1018 pll~+ Of

J. W.

~81080

h

fro8

ThVr8

for

8trlatly

KrV8VOy’8

18

al8Uly

porous

18bO#UtOry

Cat1088 for both thr hydrldm

Th8 pl’88Ona8 pKR+ = 6.3

rrportvd

SO8 2-propmol

-

he?’

wit8

for

the

ortlon

report

th8t

Of

thl8

aat of dlhydro hetaroayc188

8dduat8

whvthor

8lgmlficaat

botw88n

dtffor8nt

log

KH V.

p88udOba88 ln

ln

th8

208 8c8tonltrlle

WIT dlfforwnt181

lln88r

11no

of log 18 1.0

bro8k down

rrratlng

with

iOr

tho

Of p8mUdOb888

8p8Cl88.

It

hot8rocyclo8

uy

the

thl8

b8

lnfluonclng

88n88,

our

8olution

8nd

would

lxp8cted

b8

frm

la l-nthylth8

Kreevoy

KH with

log

KR+,'

8trUctUr8lly

8rO

hydroxide 18 thu8

8nd the

not

p8oudob880

th

th8m88lV88

C108r

r8tlo

8xp8atod

own IXIrZWnt co8p8ri8On8

l,+dlh~dronlcot1n8rld8 to-b8

8nd

‘exp8rlm8ntal

ln 8qUOOU8 2-prOpWlO1

8lkoxld8/hydroxld8

not

8uch

10-n8thyl8arid1ntum

8lXtUr8

8OlV8tiOn

h

8 80ra

the

808 w8tcr

N8tJtiOn8

wlthln

fro8 bath

in 8qu8ou8

V8ridlr8

HOweV8rr iOr

8olutionlg.

corr818tlon

‘8OlVOnt..

iOr

tha aorr88pOndlng

COntributlon8

In

88

C8n b8 88.n

a8tloa

aont81n

ia

-

8queou8

888m8 t0

vari8tlon8

form8tlon

fOr88tiOn

pKR+ V81U88

pKR+ COrr818tlOn.

V8t8r

8ffVOt8

th880

~fOrtUlh8tOlT.

81koxtd8

8OlV8tiOn

for

aorr818tlon

COrr818tlOn

which

208

by 9.10-dlhydro-10-8othy18cr1d1no.

diV8r88

con8t8nt8

-

8m88oro88ot8

dlrmct

8ff8Ct UpoIl pKK+

8OlV8llt

8trlctly

Howovor thi8

complax

the

2-prOpNtOl

8nd DIR+ = 9.0

error.

catlon36.

all

8nd p88UdOb888

18 8 Cl080

8nd furth8rmOr8 tha 81Op8

808

dlff8r8ntlal

tr8n8f8r

a8tlon8

them

rhoro88

l-b8nZyl-3-cy8nOqUlnO11nlU8

la

of qulnollnlum

for

t0

8trOllg

208 w8tor2’

3-ay8nopulaollnlu8 reduation

8

Of

8olutlon8 rOfVr

pO881b1llty

8

md J. L. BOLTDN

Burmmf

ktti8Lt

r8ductlon

much 1888

lnflu8ncod

by

8ff8Ct8.

ti 8ppr8ai8to th8 coatlnu8d fin8nci81 8upport of thl8 SciOnC88 8nd Engln88rlng Rm888rch COUnCil Of C8n8d8. K. U. KXWOVO~ for 8 preprint of r8ferunao (36).

work by th8 N8tUr81 No th8nk Profo88or

1. CRKICHTON. D. J., HAJDU, J., IYDDSKR, C., 8nd SIGNAN, D. 9. (1973) J. A8. Chom. Sot. 9B, 68SS; 2. HAJDll, J., 8nd SIGNAN, D. 9. (19721) J. Am. Chum. Sot. 97, 3324. 3. HAJDU, J., 8nd SIGNAN, D. 9. (1976) J. Am. Cha. Soa. 9Br 3524. 4. HAJDU, J., 8nd SIGNAN, D. 9. (1977) BlOChOni8try 16, 2641. 5. SHINKAI, 9.. IDX, t., HARADA, H., HANABE, O., 8nd KUNII%KX. T. (1977) J. Chem. Sot. Chem. Commun. 840. 6. SHINKAI. 9.. IDR. t.. 8nd NANABE. 0. (1978) Bull. Chom. 90~. J8p8n 6t. 3655. Chem. L8tt. 1203.7. SHINKAI, S., TSUNO, i., 8nd WANAil!, 0. (1981) 8. DJfRD, A., SHIO, T., YARAROTO, H., 8nd OKA. 9. (1981) J. Am. Chv8. SoC. 1-s

2045. 9. PCWBLL, N. ?., 8nd BRUICE, T. C. <1982) J. Am. Chum. SOC. 104, 5834. D18CU88. 10. ROBERTS, R. N. G., DSTDVIC, D., 8nd KREKVOY, R. N. <1982) ?8t’8d8y Ch8m. SOc. 74, 257. ii. POWELL, n. P., 8nd BRUICR, 1. C. (1983) J. Am. Chem. Sot. 105. 7139. Reel. Tr8v. 12. VAN LAAR. A., VAN RANESWNK. H. J., 8nd VMtHOEVBN, J. N. (1983) Chi8. P8y8-B88 102, 137. 13. BUNTING, J. W., CHKU, V. 9. P.. CHU, G., PITZGIERALD, N. P.. 8nd OH, H. T. P. (1984) Bloorg8nIc Chom. 12. 141. 14. BUNTING, J. W., 8nd PITZGKRALD, N. P. <1985X C8n. J. Chom. 15. BUNTING, J. N., 8nd SINDHUATNADJA, 9. (1981) J. Org. Chom. J. Drg. 16. BUNTING, J. W., CHKU, V. 9. I., 8nd CHU, G. (1982) 17. BUNTING, J. N., 8nd BREWER, J. C. (1985) C8n. J. Che8. 61, 18. BUNTING, J. W. <1979) Adv. Hotorocycl. Ch8m. 25, 1. s 19. BUNTING, J. W., 8nd PITZGERALD, N.-P. (1984) C8n. J. Chom. 20. BUNTING, J. W., CHKU, V. 8. P., 8nd CHU, G. (1982) J. Org. 21. KRIGWOY, n. n., 8nd LEE, I.-S. H. (1984) J. Am. Cho8. Soa.

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665.

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Chem. 1245.

47,

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