CONFORMATION-RELATED REACTION EFFICIENCY OF GLUTARIMIDES WITH PHENYLLITHIUM - STRUCTURES OF 3,3,5,5-TETRAMETHYLGLUTARIMIDE AND -HYDROXY-2-PHENYL-3,3,5,5-TETRAMETHYL-6-PIPERIDONE - X-RAY AND THEORETICAL-STUDY

Crystal structures of 3,3,5,5-tetramethylglutarimide [3,3,5,5-tetramet hylazacyclohexane-2,6-dione] (8) and the product of its reaction with phenyllithium, -hydroxy-2-phenyl-3,3,5,5-tetramethyl-6-piperidone (9), have been determined by X-ray structural methods [(8), monoclinic, P2 (1)/c, a = 7.715(2), b = 11.136(2), c = 11.707(2)Angstrom, beta = 105. 63(3)degrees; (9), triclinic, P (1) over bar, a = 6.1685(6), b = 11.14 75(10), c = 11.526(2) Angstrom, alpha = 117.100(10), beta = 103.390(10 ), gamma = 91.288(7)degrees]. Molecular structures of three different glutarimides are discussed. Their energy optimal structures were deter mined with the use of nb initio calculations. The results of crystallo graphic and theoretical studies show that the conformational changes i n glutarimide introduced by substitution with methyl groups resulted i n electron-charge distribution changes. These differences in charge di stribution are the reason for the observed variation in yields of the reaction of glutarimides with phenyllithium.