L,3,2H-benzoxazines

Reactions with N-alkylbenzisoxazolium salts Benzo-fused hetcrocyclics 4(3H)-Imino-l,3,2H-benzoxazine-2-thiones Ring expansion... 

Aq. 37%-formaldehyde in methanol added to a soln. of cyclohexylaminomethyl-hydroquinone in cold methanol, shaken 20 min., then allowed to stand 48 hrs. at room temp. 3,4-dihydro-3-cyclohexyl-6-hydroxy-l,3,2H-benzoxazine. Y 81-90%. F. e. s. W. J. Burke et al., J. Org. Ghem. 28, 1098 (1963). 

Barnes and Putnam (32,33) examined the allelopathic potential of residues and aqueous extracts of rye, and reported that benzoxazinones, 2,4-dihydroxy-l,4(2H)-benzoxazin-3-one (DIBOA) and 2,3-benzoxazolinone OA) (Figure 1) are responsible for the toxicity shown by rye residue. Patrick and Koch (34) conducted a study of the toxic substances produced as a result of microbial decomposition of plant residues, including rye and concluded that unless decomposition of the residues occurred, no toxic substances were present in the soil extract. Once in the soil, the benzoxazinones produced by rye would be susceptible to microbial transformation by various soil microbes. 

Methyl-l -(1 -oxo-2-nitro-ethyl)-E16d, 244 (En-Oxid.) 4-Nitro-l-propanoyl- VII/2a, 675 2H-l,3-Benzoxazin 8-Methoxy-2-oxo-3.4-dihydro- E4, 204 (2-OH — Ar — CH2 — NR2 + Harnstoff)... 

Nitro-3-phenyl- EI5/I. 1168 (En —N02 + R2CH-X) Cyclopentan--2H-l,3-benzoxazin 4-oxo-3,4-dihydro-EI4a/2. 742 (HO-Ar-CO-NH2 4- Keton)... 

Cyclohexan-(spiro-2)-2H-l,3-benzoxazin - -3,6-dihydro-E14a/2, 737 (H2N —Ar — CH2-OH + Keton) Cyclopropan... 

SYNS 2H-l,3-BENZOXAZINE-2,4(3H)-DIONE, 6,8-DIBROMO-2-THIO- 6,8-DIBR0M0-2-TH10-2H-l, 3-BENZOXAZINE-2,4(3H)-DIOiNE... 

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