نتایج جستجو برای: pyran
تعداد نتایج: 1454 فیلتر نتایج به سال:
Pyran (copolymer of divinyl ether and maleic anhydride) and tilorone [2,7-bis(2-diethylaminoethoxy) fluoren-9-one dihydrochloride] are host resistance-inducing agents that possess antitumor activity. The possible relationship of direct cytotoxicity to antitumor activity against the Lewis lung carcinoma and B-16 melanoma tumors was examined. Tilorone and tilorone congeners exhibited significant ...
The asymmetric unit of the title xanthene compound, C(25)H(30)O(5), contains two mol-ecules in which the pyran ring and the dimeth-oxy-phenyl ring are nearly perpendicular to one another [dihedral angles = 86.81 (8) and 84.45 (9)°]. One of the meth-oxy groups in one mol-ecule is twisted away from the phenyl ring [C-O-C-C torsion angle = -103.40 (16)°]. The pyran ring adopts a boat conformation ...
The desymmetrisation of 1,4-difuran-2-ylbutane-1,4-diol by Sharpless asymmetric oxidation gave the corresponding desymmetrised product in > 96% ee. However, the product existed as a mixture of two interconverting isomers, both of which were mixtures of anomers. The product could be trapped in high yield with a range of reagents to give stable adducts with embedded pyran-3-one, 1,6-dioxaspiro[4....
The title compound, C(16)H(10)N(2)O(5)S, was synthesized via the condesation of dihydro-thio-phen-3(2H)-one 1,1-dioxide, 1H-indene-1,2,3-trione and malononitrile in ethanol. The 2,3-dihydro-thio-phene 1,1-dioxide and pyran rings adopt envelope conformations. The mean planes through the planar part of the pyran ring and the benzene ring are nearly perpendicular, forming a dihedral angle of 88.40...
In the title compound, C(20)H(22)O(5), the tetra-hydro-pyran, cyclo-hexene and cyclo-hexane rings of the xanthene ring system adopt half-chair, half-boat and chair conformations, respectively. The mean plane of the four roughly planar atoms of the tetra-hydro-pyran ring (r.m.s. deviation = 0.111 Å) forms a dihedral angle of 82.91 (4)° with the meth-oxy-benzene group. In the crystal, mol-ecules ...
Abstract The antifungal activity of Trichoderma hamatum K01 to control Colletotrichum gloeosporioides C01 was recorded. Pathogenicity C. on citrus leaves confirmed by the Koch postulate. T. inhibited colony growth and conidia production 70.55 79.07%, respectively. Crude extracts from expressed an against C01. crude TK01-MeOH showed most potent inhibitory effect at ED 50 values 273 355 ppm, Nano...
the utilization of hydroxy sodalite (h-sod) as catalyst under solvent-free condition is described for the efficient preparation of tetrahydrobenzo[b]pyrans. these compounds are synthesized by three-component reactions of aldehydes, alkylnitriles and dimedone. h-sod that is the waste-product of zeolite manufacturing process is used as an efficient and a very inexpensive catalyst. furthermore, it...
Intra and intermolecular interactions found in the developed crystals of synthesized py-ron-2,4-dione derivatives play crucial rules molecular conformations crystal stabili-ties, respectively. In this regard, Hirshfeld calculations were used to quantitatively analyze different structures some functionalized py-ran-2,4-dione derivatives. The X-ray structure pyran-2,4-dione derivative namely (3E,...
In the title compound, C(15)H(20)O(4)S, a dioxolane ring is fused to the pyran ring of the sugar which carries a thio-phenyl substituent on the anomeric C atom. The dioxolane ring adopts an envelope conformation and the pyran ring system a distorted (4)C(1) chair. The structure is stabilized by O-H⋯O hydrogen bonds, forming centrosymmetric dimers that generate an R(2) (2)(10) ring motif. Additi...
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