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Studies in claisen rearrangements claisen rearrangement of bispropargyl ethers
TetrahedronLettersNo. 29, pp 2707 - 2710, 1973.
PergamomPrese.
Printed in &eat Britain.
STUDIES IN CLNSSN R!%ARRANGgMXNTS CIAISgN REARRANGE3&WTOF BISPROPARGYLETHEPS K.K.Balasubramanian and B. Venugopalan, Departmentof Chemistry, Indian Instituteof Technology, Madras 600036, India. (Rooeivedin UK 30 May 1973; accepted for publication7 June 1973) In recent years there has been a lot of interestin the study of multiple 1-S and sequential Claisen rearrangements
and Claisen rearrangementof aryl propargyl 17 -23 ethers6 - l6 and other related oxygen systems from syntheticand mechanisticview points.
The mechanismthat has been arrived at by S&mid &
&
11, 13.14 for the thermal
rearrangementof aryl propargylethers to chromenesis illustratedbelow:
In connectionwith our work in this area, we were interestedin studyingthe thermal rearrangementof bispropargylethers such as I, IV etc., with a view to obtain some informationregarding (i) the course and synchronousnature of the two migrations,(ii) the regiospecificity and (iii) the degree of stereoselectivity in the case of rearrangementof ethers where R #RO
while the Claisen rearrangementof bisallylethers 24 -25 of dihydroxybanzenes and dihydroxynaphthalenes are known there seems to be no
report in literatureabout the rearrangementof correspondingacetylenicethers.
In
this communicationwe wish to report a facile double Claisen migrationof the bispropargylethers I and IV to novel beneodlpyranderivatives.
_
j-g I
R=H
fZ=n
CC++ %en 2,7-bis(2'-propyn,yloxy)naphthalene, I, m.p.93_94op/e at 236; U. V.lmam 247 p
2707
No. 29
2708
1220,1015,1625 and 1605 cm-'; NMB (CDC13)$2.5 (W, t. b6.95 (2H, d, J = 10 Hz, H3 & H6).&7.6 (4H, d. J = 1.5 HE, -CCH2-),
J = 1.5 Hz,EC@,b4.7
(2H, d, J = 10 Hz, H4 & H5) and57.1 (2H, s, superimposingwith one limb of the doublet atb6.95, H1 & Hg) was refluxedin N,N-diethylaniline in a nitrogen atmospherein five 1 minutes itself, complete disappearanceof the startingmaterial was observedas indicatedby TLC and NMR anaylses. Usual work up affordeda neutral viscous dark liquid (85 $1, I. R.(CC14) 1635,1240.1025 and 1005 cm-I and nozCH band: U.Y.2:: 253, 36bshand j80Sh y
The NM R spectrum showed no signals due to olefiniomethyi or
any other methyl group.
These data clearly indicatethe absence of any monorearrange-
ment product or any methylnaphthofurans in the above rearrangedproduct. Column chromatographyof the above product over silica gel furnishednaphtho (2,1-b:7,&b) dipyran,II, as pale yellow needles,m.p.VH;9go(7" $), w hose structurewas established
IL
II
It analysedfor C16H1202 and showed the molecularion peak at 236. It readily decolourisedbromine in Ccl4 or neutral aoueous potassiumpermanganatesolution. The Ultravioletabsorptionmaximum shifted to bathochromiccomparingwith that of the startingmatarial.
Its Infrared spectrum showed a new band at 16% cm-' (I.R.CCk:
1635, 1240, 1025 and 1005 cm-') and its NI+!Rspectrumshowed an A2E$ quartet $7.05. 2H H :S 7.6. W, d, JHga= 9.5 Hz, Hb 1, a doublet at67.1 (w, JgcHd=10Hz, d' JhaHb =9.5 Hz. _a H, ), a quintet at65.75 (2H, zd ) and a quartet at5 4.75 (4H,JHeHd-5 Hz and Jallyl&.5 Hz -CCH2- ). The above data clearlyrule out the other possible structures,viz., naphtho(2,3_br7,6_b)dipyran and naphtho(2,1-b:7,bb)dipyran shown below:
No. 29
2709 I
Catalytichydrogenationof the dipyran II furnishedthe tetrahydroderivative III, -1 ; m.p.193' (Molecularion at 240; I.R.RBr1610, 1245, 1235, 1220, 1205 and 1000 cm CCl4 -G),h3.25 U.V.>,%, 248 "F; NRRCOC13$1.9 (4H, quintet,-CH2-CHH-CH2
(4H. t,fi~2-CR2-)
5 4.2 (4H, t, J = 5.5 Hz, -@X2- ), en +B2 quartet (66.8,2H, d, J = 9.5 Hz and 57.4, 2JL d, J = 9.5 Hz). The fact that the NMR spectrumof the tetrahydrocompound exhibits only an AB quartet ( integratingfor four protons only) in the aromaticregion unequivocallyestablishesthe assigned structure. The regiospecificmigrationof the propargvlgroups to 1 and 8 positionscontrastswith that reportedrecentlyfor the double 26 Fries rearrangementof 2,7- diacetoxynaphthalene to 1,6-diacetyl-2,7-dihy&opphthalene . Refluxing a solutionof 1,4-bis(2'-propynyloxy)benzene, IV, m.p.46' (molecularion I cc1 at 186; I.R.Rujo13320,3280, 2120, 1230 and 1020 cm-' ; U. V.) _4 249 and 287 rP NMR cocl.j6.9(4H, sj.64.55 (4H. d. J = 2 Hz) andi2.5 (2H, t, J = 2 Hzdin N,N-didthylaniline for 3 hrs. furnisheda neutral dark liquid (76 $1 consistingof a 1 : 1 mixture of benzo(1,2-b;4,3_b)dipyran V and benzo(l,2-b:4,5-b)dip,yran VI , as inferredfrom the followingdata:
It showed two very close moving spots in TIC ( 1 I 4 benzene-hexane)and infraredspectrum showed no 5CH band. Its NMR spectrum showed a very closely spaced sextet atd4.65 due to different-CCI$- groups, a multiplet atd5.83 due to coupled olefinicprotons,two tall singletsin between a multipletat 5 6.4 - 6.56 due to aromaticprotons and a multipletat 66 to 6.15 due to pyran ring protons ( =C&).
Catalyticreductionof the above crude
mixture affordeda white crystallinesolid melting over a range, m.p.8O-120'(86 %I. This solid also showed two very close moving spots in TLC ( 1 : 1 benzene-hexane)and its NMR spectrumshowed two singlets ( a sharp one at66.42 and a little broader one at$6.27) in a ratio of 1 : 1 ( totallyW), a multipletat&4 (4H, -OCH2- 1, a multipletat62.5 (4H, @H2-
) and a multipletat.62 (LCH,-CH2-CH2-p) . Fractionalcrystallisationof the
above solid from hexano affordedtwo crystallinesolids,1~p.119-120'(Molecularion at 190; I. R.RBr 2950, 2870, 1600, 1250, 1200, 1050, and 1010 cm-l ; U.V.),_CC++ 256 & 301 "t"!
2710
and
No. 29
m.p.78~80’.
ats6.48
The NMR spectrumof the higher melting isomer showed a sharp singlet
( 2H ), a triplet at&4 (4H, J = 6 Hz, -CCH2- 1, a tripletat62.55 (4H, J = 6 Hz,
pCH2- ) and a quintet at&2 (4H, -CH2-CH2-O- , J = 6 Hz).
The NMR spectrum of the low
melting isomer displayedclose similarityto that of the higher melting isomer in the nonaromaticregion and indicatedthat it is still contaminatedwith 25 $ of the higher g structuresVII and VIII respectivelyto the melting isomer. We are tentativelyassignin higher melting and lower melting solids on the basis of the smallerNiYRsignal width of the aromaticprotons of thehigher melting solid. Acknowledgements: The authors are thankfulto Dr. T. R.Govindachari,CBA Research Centre, Bombay for microanalyticaldata and NMR spectra,to Dr.K.Nagarajanfor highly useful discussions,to Prof.C.A.Grob,Universityof Hasle, Switzerland,for a generousgift of propargyl alcohol and to the structural chemistry section of I.I.T.,Madras
and head of
the departmentof chemistry, I.I.T.. Madras for the various spectraldata and other facilities. We are grateful to the Indian NationalScience Academyfor supportingthis research. References 1. 2. 3. 4.
C.A.Cupas,W.Schumannand E.Heyd, J.Am.Chem.Soc., 92, 4623 (191). C.A.Cupas,M.S.Kong,M.Mullinsand W.E.Heyd, Tetrahedron 34, 3157 (1971). K.C.Cooksonand N.R.Rogers, Chemical Communications, 248 (1972) Francis Weiss and A.Isard, Bull.Soc.Chim, (France(., NO.& 2033 (1967).
4 b. Francis Weiss, Quarterlv Reviews, No.& Vol.XKIV, 278 (1970). 5. B.S.Thyagarajan, K.K.BaLsubramanian and R.Bhima Rae, Chemistrv & Industrv, 401 (1967). 6. B.S.Thyagarajan, K.K.Balasubramanian and R.Bhima Rao, Tetrahedron Letters, 21, 1393 (1963). 7. B.S.Thyagarajan, K.K.Balasubramanian and R.Bhxma Rao, Tetrahedron, 21, 228971965). 8. B.S.Thyagarajan, K.K.Balasubramanian and R.Bhima Rae, J.Chem.Soc., Tin press ) 9. I.Iwai and J. Ide, Chem.Pharm.Bulletin, Tokyo, No.lO, 925 (1962). 10. I.Iwai and J. Ide, ibid., No.ll, 1042 (1963) 11. J.Zsindely and H.Schmid, Helv.Chim.Acta,s, 1510 (1968). 12. A.Jefferson and F.Scheinmann, @arterlv Reviews , 22, 391 (1968). 13. H.J.Hansen and H,Schmid, Chem.Britain, 2, 111 (1969). 14. H.Schmid, J.Zsindely and H.J.Hansen, special lecturespresentedat XXIII rd International congressof pure and applied chemistryat Boston, U.S.A. (1971). 15. J.Hlubucket, E.Ritchie and W.C.Taylor, Aust.J. Chem., _2&, 2347 (1971). 16. Morton Harfenist and Edna Thorn. J.C-rgOChem., 6, 841 (1972). 17. E. R.H.Jones, 18. D.K.Black and 19. R.Vitali and E.R.Gardi, Dalla Gazzettn _I_-Chimica Italiana. 96, 1125 (1966). 20. R.Gardi, R. Vitali and P.P.Castelli, Tetrahedron Ietters, 2, 3203 (1966). 211W.S.Trahanovsky and P.W.Mullen, J.Am. Chem.Soc & , 591;'(~;2;~6 (1972)* 22. W.S.Trahanovsky and P.W.Mullen, u. G.R.Brown, N.F.ELnore and Miss G.M.O*Do~lJm,sC~mical'Communxxtions, l& 896 (1972). 1700 (1930). $2: C. D.Hurd, Green Gard and Pilgrim, Jw z 25. Louis F.Fieser, William P.Campbell and Edward M.Fly , d, ibid 61. 2206 (1939). 26. A.P.Kuriakose and Suresh Sethna, J.Indisn Chem.Soc,, kp, No.& 1197 (1972).
PergamomPrese.
Printed in &eat Britain.
STUDIES IN CLNSSN R!%ARRANGgMXNTS CIAISgN REARRANGE3&WTOF BISPROPARGYLETHEPS K.K.Balasubramanian and B. Venugopalan, Departmentof Chemistry, Indian Instituteof Technology, Madras 600036, India. (Rooeivedin UK 30 May 1973; accepted for publication7 June 1973) In recent years there has been a lot of interestin the study of multiple 1-S and sequential Claisen rearrangements
and Claisen rearrangementof aryl propargyl 17 -23 ethers6 - l6 and other related oxygen systems from syntheticand mechanisticview points.
The mechanismthat has been arrived at by S&mid &
&
11, 13.14 for the thermal
rearrangementof aryl propargylethers to chromenesis illustratedbelow:
In connectionwith our work in this area, we were interestedin studyingthe thermal rearrangementof bispropargylethers such as I, IV etc., with a view to obtain some informationregarding (i) the course and synchronousnature of the two migrations,(ii) the regiospecificity and (iii) the degree of stereoselectivity in the case of rearrangementof ethers where R #RO
while the Claisen rearrangementof bisallylethers 24 -25 of dihydroxybanzenes and dihydroxynaphthalenes are known there seems to be no
report in literatureabout the rearrangementof correspondingacetylenicethers.
In
this communicationwe wish to report a facile double Claisen migrationof the bispropargylethers I and IV to novel beneodlpyranderivatives.
_
j-g I
R=H
fZ=n
CC++ %en 2,7-bis(2'-propyn,yloxy)naphthalene, I, m.p.93_94op/e at 236; U. V.lmam 247 p
2707
No. 29
2708
1220,1015,1625 and 1605 cm-'; NMB (CDC13)$2.5 (W, t. b6.95 (2H, d, J = 10 Hz, H3 & H6).&7.6 (4H, d. J = 1.5 HE, -CCH2-),
J = 1.5 Hz,EC@,b4.7
(2H, d, J = 10 Hz, H4 & H5) and57.1 (2H, s, superimposingwith one limb of the doublet atb6.95, H1 & Hg) was refluxedin N,N-diethylaniline in a nitrogen atmospherein five 1 minutes itself, complete disappearanceof the startingmaterial was observedas indicatedby TLC and NMR anaylses. Usual work up affordeda neutral viscous dark liquid (85 $1, I. R.(CC14) 1635,1240.1025 and 1005 cm-I and nozCH band: U.Y.2:: 253, 36bshand j80Sh y
The NM R spectrum showed no signals due to olefiniomethyi or
any other methyl group.
These data clearly indicatethe absence of any monorearrange-
ment product or any methylnaphthofurans in the above rearrangedproduct. Column chromatographyof the above product over silica gel furnishednaphtho (2,1-b:7,&b) dipyran,II, as pale yellow needles,m.p.VH;9go(7" $), w hose structurewas established
IL
II
It analysedfor C16H1202 and showed the molecularion peak at 236. It readily decolourisedbromine in Ccl4 or neutral aoueous potassiumpermanganatesolution. The Ultravioletabsorptionmaximum shifted to bathochromiccomparingwith that of the startingmatarial.
Its Infrared spectrum showed a new band at 16% cm-' (I.R.CCk:
1635, 1240, 1025 and 1005 cm-') and its NI+!Rspectrumshowed an A2E$ quartet $7.05. 2H H :S 7.6. W, d, JHga= 9.5 Hz, Hb 1, a doublet at67.1 (w, JgcHd=10Hz, d' JhaHb =9.5 Hz. _a H, ), a quintet at65.75 (2H, zd ) and a quartet at5 4.75 (4H,JHeHd-5 Hz and Jallyl&.5 Hz -CCH2- ). The above data clearlyrule out the other possible structures,viz., naphtho(2,3_br7,6_b)dipyran and naphtho(2,1-b:7,bb)dipyran shown below:
No. 29
2709 I
Catalytichydrogenationof the dipyran II furnishedthe tetrahydroderivative III, -1 ; m.p.193' (Molecularion at 240; I.R.RBr1610, 1245, 1235, 1220, 1205 and 1000 cm CCl4 -G),h3.25 U.V.>,%, 248 "F; NRRCOC13$1.9 (4H, quintet,-CH2-CHH-CH2
(4H. t,fi~2-CR2-)
5 4.2 (4H, t, J = 5.5 Hz, -@X2- ), en +B2 quartet (66.8,2H, d, J = 9.5 Hz and 57.4, 2JL d, J = 9.5 Hz). The fact that the NMR spectrumof the tetrahydrocompound exhibits only an AB quartet ( integratingfor four protons only) in the aromaticregion unequivocallyestablishesthe assigned structure. The regiospecificmigrationof the propargvlgroups to 1 and 8 positionscontrastswith that reportedrecentlyfor the double 26 Fries rearrangementof 2,7- diacetoxynaphthalene to 1,6-diacetyl-2,7-dihy&opphthalene . Refluxing a solutionof 1,4-bis(2'-propynyloxy)benzene, IV, m.p.46' (molecularion I cc1 at 186; I.R.Rujo13320,3280, 2120, 1230 and 1020 cm-' ; U. V.) _4 249 and 287 rP NMR cocl.j6.9(4H, sj.64.55 (4H. d. J = 2 Hz) andi2.5 (2H, t, J = 2 Hzdin N,N-didthylaniline for 3 hrs. furnisheda neutral dark liquid (76 $1 consistingof a 1 : 1 mixture of benzo(1,2-b;4,3_b)dipyran V and benzo(l,2-b:4,5-b)dip,yran VI , as inferredfrom the followingdata:
It showed two very close moving spots in TIC ( 1 I 4 benzene-hexane)and infraredspectrum showed no 5CH band. Its NMR spectrum showed a very closely spaced sextet atd4.65 due to different-CCI$- groups, a multiplet atd5.83 due to coupled olefinicprotons,two tall singletsin between a multipletat 5 6.4 - 6.56 due to aromaticprotons and a multipletat 66 to 6.15 due to pyran ring protons ( =C&).
Catalyticreductionof the above crude
mixture affordeda white crystallinesolid melting over a range, m.p.8O-120'(86 %I. This solid also showed two very close moving spots in TLC ( 1 : 1 benzene-hexane)and its NMR spectrumshowed two singlets ( a sharp one at66.42 and a little broader one at$6.27) in a ratio of 1 : 1 ( totallyW), a multipletat&4 (4H, -OCH2- 1, a multipletat62.5 (4H, @H2-
) and a multipletat.62 (LCH,-CH2-CH2-p) . Fractionalcrystallisationof the
above solid from hexano affordedtwo crystallinesolids,1~p.119-120'(Molecularion at 190; I. R.RBr 2950, 2870, 1600, 1250, 1200, 1050, and 1010 cm-l ; U.V.),_CC++ 256 & 301 "t"!
2710
and
No. 29
m.p.78~80’.
ats6.48
The NMR spectrumof the higher melting isomer showed a sharp singlet
( 2H ), a triplet at&4 (4H, J = 6 Hz, -CCH2- 1, a tripletat62.55 (4H, J = 6 Hz,
pCH2- ) and a quintet at&2 (4H, -CH2-CH2-O- , J = 6 Hz).
The NMR spectrum of the low
melting isomer displayedclose similarityto that of the higher melting isomer in the nonaromaticregion and indicatedthat it is still contaminatedwith 25 $ of the higher g structuresVII and VIII respectivelyto the melting isomer. We are tentativelyassignin higher melting and lower melting solids on the basis of the smallerNiYRsignal width of the aromaticprotons of thehigher melting solid. Acknowledgements: The authors are thankfulto Dr. T. R.Govindachari,CBA Research Centre, Bombay for microanalyticaldata and NMR spectra,to Dr.K.Nagarajanfor highly useful discussions,to Prof.C.A.Grob,Universityof Hasle, Switzerland,for a generousgift of propargyl alcohol and to the structural chemistry section of I.I.T.,Madras
and head of
the departmentof chemistry, I.I.T.. Madras for the various spectraldata and other facilities. We are grateful to the Indian NationalScience Academyfor supportingthis research. References 1. 2. 3. 4.
C.A.Cupas,W.Schumannand E.Heyd, J.Am.Chem.Soc., 92, 4623 (191). C.A.Cupas,M.S.Kong,M.Mullinsand W.E.Heyd, Tetrahedron 34, 3157 (1971). K.C.Cooksonand N.R.Rogers, Chemical Communications, 248 (1972) Francis Weiss and A.Isard, Bull.Soc.Chim, (France(., NO.& 2033 (1967).
4 b. Francis Weiss, Quarterlv Reviews, No.& Vol.XKIV, 278 (1970). 5. B.S.Thyagarajan, K.K.BaLsubramanian and R.Bhima Rae, Chemistrv & Industrv, 401 (1967). 6. B.S.Thyagarajan, K.K.Balasubramanian and R.Bhima Rao, Tetrahedron Letters, 21, 1393 (1963). 7. B.S.Thyagarajan, K.K.Balasubramanian and R.Bhxma Rao, Tetrahedron, 21, 228971965). 8. B.S.Thyagarajan, K.K.Balasubramanian and R.Bhima Rae, J.Chem.Soc., Tin press ) 9. I.Iwai and J. Ide, Chem.Pharm.Bulletin, Tokyo, No.lO, 925 (1962). 10. I.Iwai and J. Ide, ibid., No.ll, 1042 (1963) 11. J.Zsindely and H.Schmid, Helv.Chim.Acta,s, 1510 (1968). 12. A.Jefferson and F.Scheinmann, @arterlv Reviews , 22, 391 (1968). 13. H.J.Hansen and H,Schmid, Chem.Britain, 2, 111 (1969). 14. H.Schmid, J.Zsindely and H.J.Hansen, special lecturespresentedat XXIII rd International congressof pure and applied chemistryat Boston, U.S.A. (1971). 15. J.Hlubucket, E.Ritchie and W.C.Taylor, Aust.J. Chem., _2&, 2347 (1971). 16. Morton Harfenist and Edna Thorn. J.C-rgOChem., 6, 841 (1972). 17. E. R.H.Jones, 18. D.K.Black and 19. R.Vitali and E.R.Gardi, Dalla Gazzettn _I_-Chimica Italiana. 96, 1125 (1966). 20. R.Gardi, R. Vitali and P.P.Castelli, Tetrahedron Ietters, 2, 3203 (1966). 211W.S.Trahanovsky and P.W.Mullen, J.Am. Chem.Soc & , 591;'(~;2;~6 (1972)* 22. W.S.Trahanovsky and P.W.Mullen, u. G.R.Brown, N.F.ELnore and Miss G.M.O*Do~lJm,sC~mical'Communxxtions, l& 896 (1972). 1700 (1930). $2: C. D.Hurd, Green Gard and Pilgrim, Jw z 25. Louis F.Fieser, William P.Campbell and Edward M.Fly , d, ibid 61. 2206 (1939). 26. A.P.Kuriakose and Suresh Sethna, J.Indisn Chem.Soc,, kp, No.& 1197 (1972).