Oxazines, computational studies

A few computational studies focus on the saturated analog of 4//-l,4-oxazine, i.e., morpholine [98JCS(P2)1223, 00JCS(P2)1619, 00TL5077]. These cover the structure of lithium morpholide, cycloaddition reactions, and molecular complexes with genistein. 

Perhaps, the most common approach for the synthesis of the alkyl-substituent l,3-oxazin-6-ones 475 is the cycHzation of 3-acylaminoacrylic adds and esters, best conducted, under thermal conditions, in accordance with the rule. The reaction proceeds via the intermediate generation of acylimino ketenes 474, which can be subjected to electrocyclization into the 1,3-oxa-zin-6-one derivatives (Scheme 150(a)) (1996T3163, 1977TL1053). Cyclo-addition of acyhsocyanate 469 with the alkynyl ether was observed to give imidoylketene 474, which was in turn converted to compound 475 (1986JCS(P2)961). Results of computational studies indicate interconversion of the A/-formylazetinone 476 into l,3-oxazin-6-ones 475 via two... 

The photocatalytic N-allg lation of aniline by alcohols has been obtained over Ti02 (see Sec 1.1.1, p. 167). Photocatalitic oxidation of tri-methylamine has been studied in an annular reactor. The selective oxidation of amines to imines with aerial ojgrgen as the ultimate oxidant has been obtained by titania photocatalysis. The oxidation of triethy-lamine over niobium dioxide has been studied spectroscopically and computationally and homo and heterocoupling of benzylamine and alcohols on polycrystalline CdS have been reported. The role of photochemistry in formation and destruction of nitrosodimethylamine has been reviewed. Visible light photooxidative cyclization of amino alchols yields 1,3-oxazines. Various arylamines have been converted into heterocycles in the presence of TiOa nanopowder. ... 

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