Pseudoesters and Derivatives. XXVIII. The Reaction of 5-Methoxy-3-pyrrolin-2-one and Its 3-Bromo Derivative with Nitrogen and Sulphur Nucleophiles

Abstract

5-Methoxy-3-pyrroiin-2-one (1) reacts with dimethylamine yielding the corresponding conjugate addition product 3 a By using pyrrolidine, piperidine and diethylamine the addition product 3 is accompanied by the 5-dialkylamino-5-pytrolin-2-one 4, which in the latter case is the main component.Similar results are obtained with 3-hromo-5-methoxy-3-pyrrolin-2-one (2) and the afore-mentioned amin-.The reaction of 1 and 2 with thiois under basic catalysis gives only the conjugate addition products 7 and 13 respectively. 2The chemistry of pyrrolinones has received considerable attention as a result of the presence of i t s 3 lactam ring in Some antibiotics, in the bile pigmenrs and in the natural alkaloid jatropham, which shows 4 inhibitory activity towards the P-388 lymphmytic leukemia test system.However, the behaviour of 3-pyrroiin-2-one derivatives towards nucleaphiles appears t o have been little studied and only recentiy we have reported5 that 4-hromo-5-merhoxy-3-pyrroiin-2-one reacts with nmogen and sulphur nucleophiies t o yield the expected products of vlnylic nucleophilic substitution andlor the corresponding 4,5-his(dialkylamino)-5-pyrrolin-2-ones when secondary amines are used as nucleophiles.In the present paper we study the reaction of the same type of secondary amines and sulphur nucleophiies with the parent 5-methoxy-3-pyrrolin-2-one (1) and its 3-hromo derivative 2, in which the Michael-type addition was the expected reaction. Reaction of 5-rnethoxy-3-~rrolin-2-eThe reaction of pyrrolinone 1 with an equimolar amounr of dimethylamine affords only the expected conjugare addirion product 3a, whereas by using pyrrolidine or piperidine the addition products 3c and 3d are accompanied by substantial amounts of the corresponding 5-pyrrolin-2-ones 4c and 4d By contrast, diethylamine leads t o 5-diethylamino-5-pymlin-2-one (4b) m the main product.