A polarized, twisted, ethylene: structure of methyl 2-(1,3-dimethyl-2-imidazolidinylidene)-3-oxobutyrate dihydrate, C10H16N2O3.2H2O

Mr = 248, monoclinic, P21/n, a = 12.028 (2), b=7.168(2), c= 15.187(5)A, fl=91.88(2) °, Z= 4, V= 1308.6,~3, Din= 1.26, Dx= 1.263 Mgm -3, 2 (Cu Ka) = 1.5418 .A, g = 0.86 mm -1, F(000) = 536, T= 293 K. Final R = 5.6% for 2120 observed reflexions. Owing to the push-pull effect, the C=C bond distance is as long as 1.464 (2)/k with the twist angle about the bond 62.6.

Studies in Nonlinear Optical Materials: Structure of Methyl 2-(4-Ethyl-5-methyl- 2-thioxo-2,3-dihydro-l,3-thiazol- 3-yl) propionate

CIoH15NO282, Mr=245"0, orthorhombic, P21212 ~, a = 6.639 (2), b = 8.205 (2), c = 22.528(6)A, V= I227.2(6)A 3, z=4, Dm= 1.315, Dx= 1.326gem -3, MoKa, 2=0.7107A, 12= 3.63 cm -1, F(000) = 520, T= 293 K, R = 0.037 for 1115 significant reflections. The second-harmonicgeneration (SHG) efficiency of this compound is only 1/10th of the urea standard. The observed low second-order nonlinear response may be attributed to the unfavourable packing of the molecules in the crystal lattice.

1-Benzoyl-3-methyl-2,6-diphenyl-4-piperidone

In the title moleclue, C25H23NO2, the 4-piperidone ring adopts a boat conformation. The molecular conformation is stabilized by an intramolecular C-H center dot center dot center dot O hydrogen bond. In the crystal, molecules are connected through weak intermolecular C-H center dot center dot center dot O hydrogen bonds.

5-Methyl-2-Thiouridine in the tRNA of Candida tropicalis and Its Localization in Lysine tRNA

35S incorporation studies showed that Candida tropicalis tRNA contained two thionucleosides, one of which was identified as 5-methyl-2-thiouridine. The other thionucleoside was alkali labile, and it appeared to be an ester. Pulse-chase experiments suggested that the two thionucleosides were structurally related. 5-Methyl-2-thiouridine was present in one of the lysine tRNAs. This is the first report of the presence of this nucleoside in a yeast tRNA.

Methyl 2-methyl-2H-1,2,3-triazole-4-carboxylate

In the title compound, C5H7N3O2, all non-H atoms lie in a common plane, with a maximum deviation of 0.061 (2)° for the ester methyl C atom. The structure is stabilized by intermolecular C-H O hydrogen bonds.

Chiral Synthons from Monoterpenes.1 Stereoselective Syntheses of (-)5S, 6S, 9R-6-Isopropyl-9-Methyl-2-Oxaspiro[4.4]Nonan-3-One and (-) 3aR, 6R, 7aR-3a-Methyl-6-Isopropenylhexahydrobenzofuran-2-One

Highly stereoselective syntheses of two C-12 chiral synthons 3 and 9, mentioned in the title, starting from the monoterpenes R-1 imonene and R-carvone, using radical cyc 1 sation as key reaction, are described.

Ethyl 4-(4-hydroxyphenyl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carbox ylate monohydrate

In the title compound, C14H16N2O4 center dot H2O, the dihedral angles between the planes of the 4-hydroxyphenyl and ester groups with the plane of the six-membered tetrahydropyrimidine ring are 87.3 (1) and 75.9 (1)degrees, respectively. The crystal structure is stabilized by O-H center dot center dot center dot O and N-H center dot center dot center dot O hydrogen bonding between the water molecule and the organic functionalities.

Ethyl 4-(4-chlorophenyl)-6-methyl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate

In the title compound, C14H15ClN2O2S, the tetrahydropyrimidine ring adopts a twisted boat conformation with the carbonyl group in an s-trans conformation with respect to the C C double bond of the six-membered tetrahydropyrimidine ring. The molecular conformation is determined by an intramolecular C-H center dot center dot center dot pi interaction. The crystal structure is further stabilized by intermolecular N-H center dot center dot center dot O molecular chains and centrosymmetric N-H center dot center dot center dot S dimers.

1-(2-Chloroacetyl)-3-methyl-2,6-diphenylpiperidin-4-one

The asymmetric unit of the title compound, C20H20ClNO2, contains two crystallographically independent molecules of similar geometry. The piperidine ring adopts a distorted boat conformation in both molecules, in which the N atom assumes an almost planar configuration.

Azulenes and related substances-XI. A new azulene synthesis-azulene, 1-methyl-2-methyl- and 1, 3-dimethylazulene

The polyphosphoric acid induced intramolecular acylation of lactones has been applied to the synthesis of the bicyclo [0,3,5] decane system, and the preparation of azulene, 1-methyl-, 2-methyl- and 1,3-dimethylazulene is reported.

Structure of 5-methyl-2'-deoxycytidine 5'-monophosphate dihydrate

CloHI6N307P.2H20 , Mr = 357.2, triclinic, P1, a = 4-8520 (8), b = 8"3703 (8), c = 10.0199 (12) A, a= 104.578 (9),/3= 102.332 (13), 7=93.670(11) o, V = 381"75 A 3, Z = 1, Dx = 1"55, Dm = 1"53 Mg m -3, a(Cu Ka) = 1.5418 A,/z = 2.01 mm- l, F(000) = 188, T= 290 K, R = 0-049 for 1568 unique reflections.

N-2-(4-Methyl-2-quinolyl)phenyl]acetamide: a P1 structure with Z=4

The title compound, C18H16N2O, crystallizes in the triclinic space group P1, with four independent molecules in the asymmetric unit wherein two molecules have an irregular -ac, -ac, +ap conformation (ap, antiperiplanar; ac, anticlinal), while the other molecules exhibit a different, +ac, +ac, +ap conformation. The planar (r.m.s. deviation = 0.006 A in each of the four molecules) quinoline ring systems of the four molecules are oriented at dihedral angles of 32.8 (2), 33.4 (2), 31.7 (2) and 32.3 (2)degrees with respect to the benzene rings. Intramolecular N-H...N interactions occur in all four independent molecules. The crystal packing is stabilized by intermolecular N-H...O and C-H...O hydrogen bonds, and are further consolidated by C-H...pi and pi-pi stacking interactions centroid-centroid distances = 3.728 (3), 3.722 (3), 3.758 (3) and 3.705 (3) A].

4-Azidomethyl-7-methyl-2-oxo-2H-chromene-6-sulfonyl azide

In the title compound, C11H8N6O4S, the plane of the coumarin aromatic ring is twisted by 17.2 (2)degrees with respect to the plane of the azide group bound to the methylene substituent, whereas it is twisted by 83.2 (2)degrees to the plane of the azide attached to the sulfonyl group. The crystal structure is stabilized by weak C-H center dot center dot center dot O interactions, leading to the formation of dimers with R-2(2)(12) graph-set motifs. These dimers are further linked by weak S-O center dot center dot center dot pi and pi-pi contacts centroid-centroid distance = 3.765 (2) angstrom], leading to the formation of a layered structure.