1.3- Oxazines structure

Rice281 isolated Leucogenenol, a metabolite of Penicillium gilmanii, and attributed to it the spiro-2H-1,3-oxazine structure (123). It is also found in bovine and human liver.282... 

Two naturally occurring 1,3-oxazine derivatives with a unique, 2-chlorinated tetrahydro-l,3-oxazine structure were reported as metabolites isolated from extracts of the endophytic fungus Geotrichum sp. AL4 <2007MI1520>. Halogenated 3-(4-alkylphenyl)-l,3-benzoxazine-2,4(3//)-diones were found to exhibit antimycobacterial activity <2007AP264>. 

The bis-spirooxazine compound 18 was prepared by Kureha Chem. Ind.14 using l,5-dinitroso-2,6-dihydroxynaphthalene. The formation of the bis-oxazine structure caused a bathochromic shift, both in the unactivated compound... 

However, all support for an oxazine structure for morphine was removed when it was discovered that metathebainone (now known to be [xxxvm]), in which the function of all three oxygen atoms was known, can be degraded to a methine base, the methyl ether of which [xxxix], on heating with acetic anhydride, affords dimethylmorphol [xxvn, R = CH3] and /3-dimethylaminoethanol, proving that the latter can arise as a result of the scission of a carbon-carbon link [46],... 

Oxidation of diene-containing hydroxamic acids has been reported to give acylnitroso species which undergo spontaneous hetero-IMDA reactions to give heterobicyclic ketones. (E,E)-N-Hydroxy-5,7-dodecadienamide, upon treatment with tetrapropylammonium periodate, gave the pyrido[l,2-b][l,2]oxazine structure in high yield88. 

Dibenz[h,e]azepine-6,11-diones ent-Morphinan nomenclature, 1, 29 Morphinan, 1,2,3,4-tetrahydro-nomenclature, 1, 29 14-a-Morphinan, N-methyl-synthesis, 1, 480 Morphinans nomenclature, 1, 29 as pharmaceuticals, 1, 148 synthesis, 2, 377 Morphine, 2, 512 as analgesic, 1, 167 as metabolite of normorphine, 1, 235 as pharmaceutical, 1, 146, 147, 148 synthesis, 1, 480 Morphine alkaloids structure, 4, 534 Morphin-7-en nomenclature, 1, 29 Morphinone, dihydro-as pharmaceutical, 1, 147 Morpholine — see also 1,4-Oxazine, tetrahydrocarcinogenicity, 1, 229 corrosion inhibitor, 1, 409 metabolism, 1, 226 nomenclature, 3, 996 structure, 2, 5 synthesis, 2, 89 Morpholine, 4-aciyloyl-polymers, 1, 291 Morpholine, alkenyl-polymers, 1, 291... 

C. Ethoxycarbonylmethyl Derivatives Infrared spectroscopy indicates that equilibria of type 313 314 (R = Me, R Ac and R == Ac, R — Me) favor structure 314 in the solid state for similar work on l,4-oxazin-2-one derivatives, see references 388 and 388a. Structure 315 has also been suggested on the basis of infrared evidence. ... 

The compounds with one double bond are dihydro-1,3-oxazines, and the structures shown in Fig. 1 are possible. The conformations of dihydro-1,3-oxazine rings arc based on analogy with cyclohexcne and also on the conformational analysis of several benzo-1,3-oxazine derivatives. 

However, the very existence of l,3-4H-oxazines was questioned by Smith and Adkins. They claimed that no sufficient proof of the structure (50) exists. It appears that the problem requires further investigation. 

Infrared absorption spectra gave more information regarding the structure of 1,3-oxazine derivatives. These studies were mainly concerned with tetrahydro-ljS-oxazine " and dihydro-1,3-oxazine derivatives. - " According to Eckstein et al. a number of bands of frequencies 1150-1050, 955-925, and 855-800 cm characterize the hemiacetal bond C—0—C. Lukes et expressed the view that a triplet of bands at 1143, 1129, and 1083 cm characterized the tetrahydro-1,3-oxazine ring. However, Bergmann and Kaluszyner assigned these bands to the N—C—O system in the tetrahy dro-1,3-oxazines. 

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. 

Representatives of all three types of isomeric 1,3-oxazines 82-84 (X = O) and 1,3-thiazines 82-84 (X = S) and of the corresponding partially hydrogenated derivatives are known. However, no tautomeric interconversions between these structures have been observed. 

Chemical Name 3,4 dimethyl-2-phenylmorphQline bitartrate Common Name 3,4-dimethyl-2-phenyltetrahydro-1,4-oxazine bitartrate Structural Formula ... 

Another chiral auxiliary used in diastereoselective addition reactions is the 1,3-oxazine derivative 4a which shows a close structural resemblance to the 1,3-oxathiane 16 (vide supra). However, in contrast to the oxathiane, 4a cannot be readily acylatcd in the 2-position. Therefore, the benzoyl derivative 4b was prepared by condensing amino alcohol 3 with phenylglyoxal. 

Motpholines are a chemical class of organic compounds with the six-membered ring tetrahydro-1,4-oxazine, as their basic structure. 

Indolines, benzoxazole, and benzothiazole are possible as 2-methylene heterocycles. The number of known spirooxazine derivatives is much less than for the spiropyrans. This may be partly due to lack of many substituted o-nitrosonaphthols and partly due to lack of sufficient stability of spiro-oxazines. The structures of parent spirooxazines and the Xmax of their photomerocyanine forms are listed in Table 5. The Xmax of the colored forms of compounds 41-43 are not described in the literature. 

The stereostructure of ethyl OT-4a,7-//-7-phenyl-8-cyano-2-oxo-2,3,4,4a,7,8-hexahydropyrido[l,2-A [l,2]oxazine-8-carboxylate was confirmed by X-ray crystallography. It confirmed a trans-nng junction <20000L4007>. The structure of 2,4-diphenyl-7-o-hydroxyphenyl-5,6-dihydropyrido[2,Ttf]phthalazinium perchlorate 21 has also been established by X-ray crystallographic analysis <1995IZV296>. 

The crystal structures of 4-phenyl-2- 4-[4-(2-pyrimidinyl)piperazin-l-yl]butyl -2,3,5,6,7,8-hexahydro-177-pyrido[l,2-c][l,3]oxazine-l,3-dione <1995ZK899>, 4-cyano-l-phenyl-l-trifluoromethyl-2,3-dihydro-l/7-pyrido[l,2-r-]pyrimidin-... 

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