Amine-boryl tosylates

INORG.

NUCL.

CHEM.

LETTERS

Vol.

7,

pp.

99-101,

1971.

Pergamon Press.

Printed in Great Britain.

AMINE-BORYL TOSYLATES G.E. Ryschkewitsch D e p a r t m e n t of C h e m i s t r y , U n i v e r s i t y of F l o r i d a , G a i n e s v i l l e , F l o r i d a (Received 19 August 1970)

We w i s h to r e p o r t the i s o l a t i o n and c h a r a c t e r i z a t i o n of b o r y l t o s y l a t e s in which a b o r a n e unit c a r r y i n g a p - t o l u e n e s u l f o n a t e substituent i s c o o r d i n a t e d to a t e r t i a r y amine.

Such compounds have so far not been r e p o r t e d , although r e l a t e d

d i a l k y l b o r y l sulfonates not coordinated to a m i n e have been d e s c r i b e d in a r e c e n t v e r y i n t e r e s t i n g communication. 1 W h e r e a s the l a t t e r compounds w e r e a i r - a n d m o i s t u r e s e n s i t i v e and a p p a r e n t l y w e r e quite r e a c t i v e t o w a r d s substitution of the sulfonate group, the p r e s e n t compounds can b e handled in the a t m o s p h e r e and a r e l e s s r e a c t i v e t o w a r d s substitution of the t o s y l a t e by a m i n e s than a r e the c o r r e s p o n d ing i o d o - d e r i v a t i v e s . 2 T r i m e t h y l a m i n e - b o r y l p-toluenesulfonate was p r e p a r e d in quantitative yield and good purity by the r e a c t i o n of s t o i c h i o m e t r i c quantities of anhydrous p toluenesulfonic acid 3 and t r i m e t h y l a m i n e - b o r a n e in 0.4M solution in d r y benzene. Rapid hydrogen evolution o c c u r e d at r o o m t e m p e r a t u r e o r below to afford, after solvent r e m o v a l , a 99.6% yield of the sulfonate a c c o r d i n g to the equation. (CH~)sNBH~

+

CH3C~I.SOzH

4

H2

+

CHaC~I~SOzBH~N(CHs)3

The c r u d e product (rap 98) was r e c r y s t a l l i z e d f r o m hot b e n z e n e - p e t r o l e u m e t h e r , to give an a n a l y t i c a l l y p u r e compound (rap 99-100.5).

Anal. Calcd. for

CzoHzeBNO3S: C, 4 9 . 4 0 ; H , 7 . 4 6 ; N , 5.76. Found: C, 4 9 . 4 0 ; H , 7.37; N, 5.68. x The proton n m r c o n s i s t e d of two s i n g l e t s c o r r e s p o n d i n g to methyl groups at 6(ppm) 2.38 (3H) and 2 . 5 2 (9H), and of two doublets (J=8Hz) c o r r e s p o n d i n g to the r i n g p r o t o n s , c e n t e r e d at 6 (ppm) 7.25 (2I-I) and 7.72 (2H).

The i n f r a r e d s p e c t r u m

-I

showed a b s o r p t i o n s at 2420 and 2320 cm indicative of the p r e s e n c e of a BH~ group. R e a c t i o n with a second equivalent of p-toluenesulfonic acid r e q u i r e d r e f l u x t e m p e r a t u r e to f o r m the d i - t o s y l a t e d e r i v a t i v e .

The c r u d e product, obtained by

p r e c i p i t a t i o n f r o m benzene or CH~CI~ with p e t r o l e u m e t h e r , contained about 7 mole% t r i m e t h y l a m m o n i u m s a l t which could b e r e m o v e d by f r a c t i o n a l c r y s t a l lization f r o m C H ~ C ~ - p e t r o l e u m e t h e r .

Yield 50%, mp 156-157 (dec).

Anal.

x) A l l s p e c t r a w e r e taken in CHiCle; c h e m i c a l shifts a r e downfield f r o m i n t e r n a l tetramethylsilane. 99

100

AMINE-BORYL TOSYLATES

Calcd. for C1,H~4~BNO~S~: C, 49.49;H, 5 . 8 4 ; N , 3.39. N, 3.31.

2520 cm

Found: C, 49.12;H, 5.81;

The proton nmr gave the expected resonances at 5(ppm) 2.43 (6H),

2.55 (gH), 7.22 (4H) and 7.63 (4H). J=SHz.

Vol. 7, No. 1

The latter two resonances were doublets with

The infrared spectrum showed the expected single B-H stretching at -1

Both tosylate derivatives reacted r e a d i l y with elemental bromine in CH~CI~ with complete substitution of the boron-attached hydrogens by halogen.

Thus the

monotosylate afforded (CH~)~NBBr2(SO3CsH4CH3), mp 134-136. Anal. Calcd. for CloI-I~eBBr~NO~S: C, 29.96; H, 4.02; Br, 39.86; N, 3.49. H, 3.88, Br, 39.90; N, 3.51.

Found: C, 30.08;

P r o t o n n m r , 5(ppm): 2.43 (3H), 2.89 (9H), 7.31

(2H, doublet J=SHz) 7.83 (2H, doublet, J=Hz).

The disosylate gave

(CI-I3)~NBBr(SOsCeI-I~CH3)2, mp 133. 5-135. Anal. Cal~J. for C17Ha.~BBrNOeS~: C, 41.48;H, 4.71; Br, 16.24; N, 2.85. N, 2.88.

Found: C, 41.76;H, 4.72; Br, 16.15;

Proton nmr 5(ppm): 2.43 (6H), 2.78 (9H), 7.28 (4H, doublet, J=SHz),

7.78 (4H, doublet, J=SHz).

The resonances of the N-methyl protons were quartets 4 in both t r i - s u b s t i t u t e d boranes, indicative of a H-C-N-B-XnY~_ n grouping. The t r i m e t h y l a m i n e - b o r y l tosylates failed to r e a c t with trimethylamine or 4-methylpyridine at room t e m p e r a t u r e , but the monotosylate gave a mixture of +5 +6 70% (CHsCr~I~)~BI-I~ and 30% (CHsCsHtN)(CHs)sN)BI~ on heating with 4-methylpyridine. In contrast, the tosylate of 4-methylpyridine borane, prepared in situ and then saturated in benzene solution with trimethylamine, gave within +

one hour at room temperature, an 85% yield of (CHsCsHtN)[(CH3)aN]BH~ isolated as P F s - salt, rap. 146-147.5, lit: 7 146.5-147. This difference in reactivity between t r i m e t h y l a m i n e - and 4-methylpyridineboryl tosylates p a r a l l e l s the reactivity difference in the corresponding iodo 6 derivatives towards d i s p l a c e m e n t of halide, but on an absolute scale tosylate seems to be less r e a d i l y displaced than is iodide. Thus, when 4-methylpyridinemonoiodoborane was treated with one equivalent of anhydrous p-toluenesulfonic acid in benzene and the resulting solution was saturated with trimethylamine, a precipitate resulted which on treatment with aqueous NH~PFs produced the + sulfonate-substituted cation (CHq-C~I4N)[(CH~)~N]BH(SO3Cd-I4CH3) , P F s - , +

rap. 172 (with d e c . ) . N, 5.78.

Anal. Calcd. for ClsI-I~BN~)~S PFe ; C, 40.51; H, 5. 00;

Found: C, 40.20; H, 4.93; N, 5.58.

This is the compound expected

from displacement of iodide; displacement of sulfonate should have produced +

(CHsCr~4N)[(CH3)sN]BHI , PFs .

Vol. 7, No. 1

AMINE-BORYLTOSYLATES Acknowledgement

P a r t i a l support of this work under NIH Grant GM-13650 is g r a t e f u l l y acknowledged. References 1.

S. T r o f i m e n k o , J . A m . Chem. S o c . , 91, 2139 (1969).

2.

G . E . R y s c h k e w i t s e h and K. Zutshi, Inorg. C h e m . , 9, 411 (1970) and references therein.

3.

N . G . K h o z a n e r , Can. J. C h e m . , 31, 585 (1953).

4.

G . E , R y s c h k e w i t s c h and W . J . R a d e m a k e r , J . Magn. R e s . , 1, 584 (1969).

5.

K . C . Nainan and G . E . R y s c h k e w i t s e h , Inorg. C h e m . , 7, 1316 (1968).

6.

K . C . Nainan and G . E . R y s c h k e w i t s c h , J . A m . Chem. S o e . , 91, 330 (1969).

7.

G.E° R y s c h k e w i t s c h and J . M . G a r r e t t , J. Am. Chem. S o e . , 90, 7234 (1968).

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