In this work, we reported on the synthesis and characterization of (Z)-4-oxo-4-ureido-but-2-enoic acid and p-toluenesulfonic acid 3-nitrophenyl ester and their detailed crystal structure information were studied. The crystallization of (Z)-4-oxo-4-ureido-but-2-enoic acid results in reduced π -conjugation in the molecule and weaker intra-molecular hydrogen bonding. The main driving force for the molecular self-assembly of (Z)-4-oxo-4-ureido-but-2-enoic acid was found to be the strong intermolecular hydrogen bonds . Compared with (Z)-4-oxo-4-ureido-but-2-enoic acid with six type of strong H-bonds, p-toluenesulfonic acid 3-nitrophenyl ester possesses much lower melting point (110–111°C), average packing energy (−3.7 kcal mol −1 ), molecular deformation energy (−0.6 kcal mol −1 ) and highest torsional angle change (9.3°). This can be ascribed to the week intermolecular interaction between center molecule and adjacent molecules.
Yan-Qing Wang,Wen-Qing Yan,Li-Xue Nie,Ping-Ping Luan,Chao-Qun Li
C 20 H 22 Cu 3 N 8 O 10 , monoclinic, C 2/ c (no. 15), a = 12.0766(11) Å, b = 16.2778(14) Å, c = 14.7605(13) Å, β = 97.8580(10) ∘ , V = 2874.4(4) Å 3 , Z = 4, R
gt ( F ) = 0.0420, wR
ref ( F
2 ) = 0.0988, T = 298.15 K.
Mingji Xiao,Fangling Zheng,Mengxuan Xiao,An Qi,Huiqiang Wang,Qianying Dai
In China, Lu'an Guapian (LAGP) tea consists of tea leaves without tea buds or stems. In this study, we evaluated the aromatic characteristics of LAGP by sensory analysis, aroma extract dilution analysis (AEDA), and odor activity values. The sensory analysis revealed that LAGP had cooked soybean-like, cooked chestnut-like, roasted, cooked corn-like, fishy, fruity, floral, and grass aromas. Aroma-active compounds from LAGP were identified by solvent extraction-solid phase extraction (SE-SPE) and headspace-solid phase microextraction (HS-SPME), and subjected to AEDA. A total of 91 aroma-active compounds were identified by SE-SPE-AEDA with flavor dilution (FD) factors ranging from 1 to 4096. A total of 66 aroma-active compounds were identified by HS-SPME-AEDA with FD of 1 to 128. Nine compounds with FD ≥64 and OAVs ≥1 were major aroma-active compounds to the aroma of LAGP tea: raspberry ketone (raspberry), ( E )- β -ionone (floral, raspberry), dimethyl sulfide (cooked corn-like), indole (animal), phenylacetaldehyde (floral, honey-like), 2-ethyl-3,5-dimethylpyrazine (roasted), ( Z )-4-heptenal (cooked soybean-like, fishy), ( Z )-jasmone (jasmine), and geraniol (rose).
危险品化学品经营许可证（带存储）