Reactions of alpha -aminonitriles. III. Reactions of alpha -aminonitriles and Grignard reagents. Effect of the degree of branching and chain length on the course of the reactions

Abstract

The reactions of the 4 isomeric butylmagnesium chlorides with alpha -piperidinoacetonitrile (I) and 4 of its alpha -substituted derivs. of general formula II were studied. I underwent adduct formation and dimerization, to give isomeric butyl piperidinomethyl ketones (III) and the dimer 3-amino-2,3-dipiperidinocrotononitrile (IV). The other compds. underwent Grignard exchange to give V (R2 = isomeric Bu), dimer exchange, VI, or H exchange to give VII. Reaction was incomplete in some cases. These results show the effect of branching in the nitrile and in the Grignard. The b.p. of the products are given (product and b.p./mm. given): III (R = Bu), 120 Deg/15; III (R = iso-Bu), 110-13 Deg/15; III (R = sec-Bu), 116-18 Deg/15; IV, 167-9 Deg/0.3; V (R = H, R1 = Me, R2 = Bu), 92-3 Deg/13; V (R = H, R1 = Me, R2 = iso-Bu), 88 Deg/13; V (R = H, R1 = Me, R2 = tert-Bu), 82 Deg/13; VI (R = H, R1 = Me), 148 Deg/15 and 295-8 Deg/715; VII (R = H, R1 = Me), 130-2 Deg/720; V (R = H, R1 = Pr, R2 = Bu), 105 Deg/13; V (R = H, R1 = Pr, R2 = iso-Bu), 104 Deg/13; VII (R = H, R1 = Pr), 171-3 Deg/725; V (R = R1 = Me, R2 = Bu), 94 Deg/13; V (R = R1 = Me, R2 = iso-Bu), 94 Deg/13; VII (R = R1 = Me), 145-8 Deg/720; V (R = Me, R1 = Et, R2 = Bu), 110-12 Deg/-13; V (R = Me, R1 = Et, R2 = iso-Bu), 110-11 Deg/13; VII (R = Me, R1 = Et), 173-5 Deg/715. The reactions mechanisms and the effects of chain branching on the reactions are discussed.