Base dependent purported synthesis of congested 2-aminobenzylamines and tetrahydro-2-oxoquinazolines from 2-pyranones

• Published in: Tetrahedron 2009-02, Vol.65 (8), p.1635-1638
• Main Authors: Farhanullah, Samrin, Farhana, Ram, Vishnu Ji
• Format: Article
• Language: English
• Subjects: Chemistry; Exact sciences and technology; Heterocyclic compounds; Heterocyclic compounds with o, s, se, te hetero atom and condensed derivatives; Heterocyclic compounds with several n hetero atoms in the same ring, in separated rings or in fused rings; Kinetics and mechanisms; Noncondensed benzenic compounds; Organic chemistry; Preparations and properties; Reactivity and mechanisms
• ISSN: 0040-4020; 1464-5416
• DOI: 10.1016/j.tet.2008.12.041

An expeditious and concise synthesis of highly congested 2-amino-3-aminomethyl-5-methylsulfanyl/- sec-aminobiphenyl-4-carbonitrile 4 and 1- tert-butoxycarbonyl-6- sec-amino-8-aryl-5-cyano-2- oxo-1,2,3,4-tetrahydroquinazoline 5 has been delineated through base catalyzed ring transformation of 6-aryl-4-methylsulfanyl/- sec-amino-2 H-pyran-2-one-3-carbonitrile 1 with 1,3-bis( tert-butoxycarbonylamino)-2-propanone 2, followed by TFA catalyzed hydrolysis of the intermediate [3- tert-butoxycarbonylaminomethyl-4-cyano-5-methylsulfanyl/- sec-aminobiphenyl-2-yl]carbamic acid tert-butyl ester 3 in moderate yield. The mechanism of formation of 5 has been established through isolation and transformation of the intermediate 3 to the 1- tert-butoxycarbonyl-6- sec-amino-8-aryl-5-cyano-2- oxo-1,2,3,4-tetrahydroquinazoline. [Display omitted]