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Observations on the Reactions of Isocyanoacetane Esters with Isothiocyanates and Isocyanates

1987; Elsevier BV; Volume: 26; Issue: 3 Linguagem: Inglês

10.3987/r-1987-03-0651

1881-0942

Daniel M. Solomon, Razia Rizvi, James J. Kaminski,

Synthesis and Reactivity of Sulfur-Containing Compounds

m e reactions of the w t a l s a l t s of a-isocyanoacetate e s t e r s with isothiocyanates and isccyanates =re examined.me e f f e c t s of mrliQing the reaction paramstem on t h e altcm of the reaction (Schem?I1 of methyl a-isocyanoacetate ( G I with phew1 isothiocyanate (21 have been studied, thus providing elhawed understanding of the factors c m t r o l l i n g t h i s u s a h 1 Crocess.Specifically, the substantial influence of reaction temperature an3 node of addition of reagents on the yield of main erafuct, thiazole &--as wll a s the novel observation of the formation of imidazole 4 as a minor, but r e p r d u c i b l e and significant, side-prdct--has teen docwrented.Previausly reported oxazole formation i n the low-t-rature reaction of the l i t h i o derivative of L w i t h phenyl isothiocyanate i.2) was not observed i n the present study; m l y thiazole (&I was detected under these 'L, 14. or.those exgriments i n which the products were not isolateed.quantitative BPLC data were used t o calculate the aooroximte product vields.A c m s -c h s k of the gistrihution f i g u r e s ~c o l i i c ? l by IPLC and isolation was mrle in one exnerimcnt ( Y 4 .Table I1 an4 s q q e s t e d a close com?soon.loncehetween the w t h d s .In two experimnts i n xhich neither isolation nor IlPliC analysis was oerfo-1, PMR i n t q r a t i o n data were used.Inasmuch as ox objective was to delineate broad trends in product d i s t r i b u t i o n , rather than to e s t a b l i s h hiqhly precise corparisons of r e l a t i v e l y close results, data obtained by the PMR mtkd wcre reqarled a s suEEiciently c m a r a b l c t o justiEy t h e i r inclusicn.