10.1002/ejoc.200900216
The research presents a novel and efficient method for synthesizing pyrimido[5,4-d]pyrimidine N-oxides, which are of significant interest in drug development due to their structural similarity to purines and their potential biological activities. The study explores the reaction of benzylhydroxylamine with 6-cyanopurines to form 7-benzyloxy-8-imino-7,8-dihydropyrimido[5,4-d]pyrimidines, which upon treatment with hydrochloric acid, yield the desired N-oxides. The study concludes that the solubility of the hydrochloride of the intermediate pyrimido-pyrimidines in the reaction solvent plays a crucial role in determining the final product, with soluble hydrochlorides leading to the rearranged product and insoluble ones yielding the N-oxides. This work provides a mild and selective approach to synthesizing these heterocyclic compounds, which could have implications for the development of new pharmaceutical agents.
10.1246/cl.1978.1057
The study presents a novel method for the preparation of primary amines using N-benzylhydroxylamine and 2-fluoropyridinium salt. N-benzylhydroxylamine serves as a synthetic intermediate with two functional groups (an amino group and a hydroxyl group), which is alkylated by alkyl halides or olefinic compounds to form N-alkyl-N-benzylhydroxylamine. This intermediate is then dehydrated using 2-fluoropyridinium salt and triethylamine to yield N-benzylidenealkylamine, which is subsequently hydrolyzed in dilute hydrochloric acid to produce the desired primary amine. The method involves three key reactions: N-alkylation of N-benzylhydroxylamine, dehydration using the 2-fluoropyridinium salt, and acid hydrolysis of the resulting imine. The study demonstrates the effectiveness of this approach through the synthesis of various primary amines, achieving good yields and highlighting the utility of the reagents and reaction conditions employed.