- Enantiomerically pure poly(oxymethylene) helices: Correlating helicity with centrochirality
[作者:Eppacher, S; Giester, G; Bats, JW; Noe, CR,期刊:Helvetica Chimica Acta, 页码:581-597 , 文章类型: Article,,卷期:2008年91-4]
- A first series of enantiomerically pure helical oligo (formaldehyde)s (=oligo(oxymethylen)s) 16-20 was synthesized. To induce the chiral uniformity of the helices, we used (IS)-2,2-dimethyl-l-phenylpropan-1-ol (14) to ge...
- Synthesis of (+)-13-stemarene and (+)-18-deoxystemarin: Expeditious preparation of the key 6-exo-Hydroxybicyclo[2.2.2]octan-2-one ethylene dithioacetal
[作者:Leonelli, F; Caschera, B; Silvestri, L; Prastaro, A; Corso, G; Ceccacci, F; La Bella, A; Migneco, LM; Bettolo, RM,期刊:Helvetica Chimica Acta, 页码:598-607 , 文章类型: Article,,卷期:2008年91-4]
- An expeditious preparation of the 6-exo-hydroxybicyclo[2.2.2]octan-2-one ethylene dithioacetal 2b, a key intermediate in the synthesis of (+)-13-stemarene (4) and (+)-18-deoxystemarin (5) is described. Compound 2b was ob...
- Novel aspects of a convenient synthesis and of electroproperties of derivatives based on diphenylamine
[作者:Idzik, K; Soloducho, J; Cabaj, J; Mosiadz, M; Lapkowski, M; Golba, S,期刊:Helvetica Chimica Acta, 页码:618-627 , 文章类型: Article,,卷期:2008年91-4]
- The substituted monomers 4a,c,d, 5a,b, 6a, 7a,b, and 8a of novel poly(diphenylamines), possessing the respective photochromic groups, were synthesized by the Stille cross-coupling methodology (Scheme). The hyperbranched ...
- Four new neoclerodane diterpenoids from Ajuga decumbens
[作者:Huang, XC; Qin, S; Guo, YW; Krohn, K,期刊:Helvetica Chimica Acta, 页码:628-634 , 文章类型: Article,,卷期:2008年91-4]
- Four new neoclerodane diterpenoids, 15-epilupulin A (1), 6-O-deacetylajugamarin (2), and ajugadecumbenins A (3) and B (4), were isolated from the whole plants of Ajuga decumbens. Their structures were elucidated on the b...
- Iridoid glycosides from Gardenia jasminoides ELLIS
[作者:Fu, XM; Chou, GX; Wang, ZT,期刊:Helvetica Chimica Acta, 页码:646-653 , 文章类型: Article,,卷期:2008年91-4]
- Three new iridoid glycosides, 4 ''-O-[(E)-p-coumaroyl]gentiobiosylgenipin (1), 6'-O-[(E)-caffeoyl]deacetylasperulosidic acid methyl ester (2), and 6'-O-[(E)-sinapoyl]gardoside (3), together with seven analogues, 4-10, we...
- Ring opening of 2-(benzylamino)-2H-1,4-benzoxazin-3(4H)-ones and 2-bromo-2H-1,4-benzoxazin-3(4H)-ones
[作者:Ilas, J; Kikelj, D,期刊:Helvetica Chimica Acta, 页码:654-664 , 文章类型: Article,,卷期:2008年91-4]
- Substituted 2-(benzylamino)-2H-1,4-benzoxazin-3(4H)-ones are unstable under alkaline and acidic conditions, undergoing opening of the benzoxazinone ring. 2-Bromo-2H-1,4-benzoxazin-3(4H)-ones show similar degradation unde...
- Triterpenoids from the edible leaves of Photinia serrulata
[作者:Song, YL; Wang, YH; Lu, Q; Qiao, HJ; Cheng, YX,期刊:Helvetica Chimica Acta, 页码:665-672 , 文章类型: Article,,卷期:2008年91-4]
- Five new triterpenoids, serrulatins A-E (1-5), including two new artifacts, together with ten known serrulatins, were isolated from the edible leaves of Photinia serrulata after extraction and purification. Their structu...
- Preparation of two diastereoisomeric decalin synthons and (-)-ambrox
[作者:Xie, YP; Li, BG; Luo, YG; Chen, XZ; Zhang, GL,期刊:Helvetica Chimica Acta, 页码:734-740 , 文章类型: Article,,卷期:2008年91-4]
- Two diastereoisomeric decalins, (2S,4aS,5S,6R)- and (2S,4aS,5R,6R)-5-(2-hydroxyethyl)-1,1,4a,6-tetramethyldecalin-2,6-diol (5 and 6) were prepared from the degradation products of oleanolic acid. Starting from 6, (-)-amb...
- Novel polyketides isolated from Streptomyces sp.
[作者:Li, J; Lu, CH; Shen, YM,期刊:Helvetica Chimica Acta, 页码:741-745 , 文章类型: Article,,卷期:2008年91-4]
- From the endophytic strain Streptomyces sp. CS of Maytenus hookeri, five novel type III polyketides, compounds 1-5, were isolated. Their structures were elucidated by spectroscopic analyses including 1D- and 2D-NMR exper...
- Modified cyclodextrins as enantioselective hosts for amino acids
[作者:Kumar, VP; Suryanarayana, T; Nageswar, YVD; Rao, KR,期刊:Helvetica Chimica Acta, 页码:753-758 , 文章类型: Article,,卷期:2008年91-4]
- Two modified beta-cyclodextrins, H-2 and H-3, having a flexible appended moiety were studied for the chiral discrimination of the enantiomers of various amino acids by means of fluorescence as signaling option. These hos...
- A new diterpenoid and a new diterpenoid alkaloid from Aconitum coreanum
[作者:Yang, CH; Wang, XC; Tang, QF; Liu, WY; Liu, JH,期刊:Helvetica Chimica Acta, 页码:759-765 , 文章类型: Article,,卷期:2008年91-4]
- A new diterpenoid, guan fu diterpenoid A (1), and a new diterpenoid alkaloid, guan fu base S (2), were isolated from the Chinese medicinal herb Aconitum coreanum (LEVL.) RAPAICS, together with five known diterpenoid alka...
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