Xiaoji Wang

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Let s = (s 1 ,. .. , s m) and t = (t 1 ,. .. , t n) be vectors of non-negative integer-valued functions with equal sum S = m i=1 s i = n j=1 t j. Let N (s, t) be the number of m × n matrices with entries from {0, 1} such that the ith row has row sum s i and the jth column has column sum t j. Equivalently, N (s, t) is the number of labelled bipartite graphs(More)
We obtain the asymptotic number of labelled tournaments with a given score sequence in the case where each score is n/2 + O(n 3/4+ǫ) for sufficiently small ǫ > 0. Some consequences for the score sequences of random tournaments are also noted. The method used is integration in n complex dimensions.
In the present paper, we report an efficient total synthesis of a marine alkaloid, rigidin E. The key tetrasubstituted 2-amino-3-carboxamidepyrrole intermediate was synthesized by cascade Michael addition/intramolecular cyclization between N-(2-(4-(benzyloxy)phenyl)-2-oxoethyl)methanesulfonamide and 3-(4-(benzyloxy)phenyl)-2-cyano-N-methylacrylamide.(More)
Nostosins A and B were isolated from a hydrophilic extract of Nostoc sp. strain from Iran, which exhibits excellent tryps inhibitory activity. Nostosin A was the most potent natural tripeptide aldehyde as trypsin inhibitor up to now. Both R- and S-2-hydroxy-4-(4-hydroxy-phenyl) butanoic acid (Hhpba) were prepared and incorporated into the total synthesis of(More)
Ieodomycin B, which shows in vitro antimicrobial activity, was isolated from a marine Bacillus species. A novel asymmetric total synthetic approach to ieodomycin B using commercially available geraniol was achieved. The approach involves the generation of 1,3-trans-dihydroxyl at C-3 and C-5 positions via a Crimmins-modified Evans aldol reaction and a(More)
Itralamides A and B were isolated from the lipophilic extract of Lyngbya majuscula collected from the eastern Caribbean. Itralamide B (1) showed cytotoxic activity towards human embryonic kidney cells (HEK293, IC50 = 6 μM). Preliminary studies disapproved the proposed stereochemistry of itralamide. In this paper, we will provide a full account of the total(More)
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