Starting from commercially available (-)-quinic acid, the enantioselective total syntheses of trichodermamides A and B were achieved. The key reactions involve the stereoselective construction of the oxazine ring via an intramolecular epoxide ring opening reaction and an EDCI-assisted peptide coupling reaction.

Bacterial biofilms are estimated to be associated with over 65 percent of all nosocomial infections. However, no therapeutics have been approved by the FDA which directly mediate biofilm formation or persistence. Herein we report oxazine as a highly potent inhibitor, disperser and in the presence of the appropriate antibiotic eradicator of V. cholerae biofilms.

The asymmetric unit of the title compound, C(20)H(24)N(2)O(2), contains one half-mol-ecule, which is completed by inversion symmetry. In the crystal, mol-ecular chains are formed through non-classical C-H⋯O hydrogen bonds, formed between axial H atoms of the oxazine ring and a O atom of a neighboring mol-ecule.

Yb(NTf(2))(3)-catalyzed [3 + 3] cycloaddition between isatin ketonitrones and cyclopropanes is described. A variety of spiro[tetrahydro-1,2-oxazine]oxindoles were obtained in moderate to good yields along with good regioselectivities. This is the first example of the intermolecular [3 + 3] cycloaddition between ketone-derived nitrones and cyclopropanes.

Novel dihydro-1,3-oxazinoporphyrins and naphtho[e]bis(dihydro-1,3-oxazinoporphyrin) derivatives, in which the porphyrin macrocycle is covalently linked to the dihydro-1,3-oxazine ring system were successfully synthesized from 5-(4-aminophenyl)-10,15,20-triphenylporphyrin in good yields. The structures of the target products were established on the basis of spectral data and elemental analyses.

In the title compound, C(25)H(19)NO(3), the oxazine ring displays a half-chair conformation. The fused benzene ring is nearly parallel to the naphthyl ring system, the dihedral angle between this benzene ring and the naphthyl system being 8.52 (11)°. The imino group is not involved in hydrogen bonding in the crystal structure.

The title compound, C10H13NO2, crystallizes with two crystallographically independent mol-ecules of similar geometry in the asymmetric unit; the six-membered oxazine rings adopts a half-chair conformation. Neither hydrogen bonds nor π-π inter-actions are observed in the crystal structure.

The title compound, C(10)H(8)BrCl(2)NO(2), is a target mol-ecule in our research on herbicide safeners. The oxazine ring has an envelope conformation, with puckering parameters close to ideal values [Q = 0.498 (3) Å, θ = 53.7 (3)° and ϕ = 253.4 (4)°]. The crystal structure is stabilized by C-H⋯O, C-H⋯Cl and C-H⋯Br inter-actions.

The title compound, C14H14N2O3, is the exo isomer with a syn arrangement of two O atoms in the isoxazole and oxazine rings. The dihedral angle between the isoxazole and phenyl rings is 60.38 (4)°. In the crystal, weak C-H⋯O hydrogen bonds link the mol-ecules, forming a three-dimensional network. The isoxazole O atom is an acceptor for three of these hydrogen bonds.