A Novel Synthesis of Dimethyl Malonate by Carbonylation of Methyl Chloroacetate Catalyzed by Cobalt Complex

Dimethyl malonate (DMM) is an important organic synthesis intermediate. Traditional synthetic method by reaction of mono-chloroacetic acid with sodium cyanide1 is poisonous and complicated. Therefore, an interest in green synthesis routes of DMM has risen greatly. The several processes for preparing DMM by carbonylation of methyl chloroacetate catalyzed by Co2(CO)8 have been reported2~5. However, Co2(CO)8 is unstable and must be prepared under high pressure (12 Mpa). Moreover, the yield…     

The Synthesis of 19-Nor-1α, 25-dihydroxy-22-oxo-vitamin D_3

Since the last decade, there has been a growing interest in the development of analogues of 1(, 25- dihydroxyvitamin D3 1 with low calcemic effect but increased cell differentiating ability1. Among side chain and the A-ring modifications of 1, the 1(, 25- dihydroxy-22-oxo-vitamin D3 22 and 19-nor-1(, 25- dihydroxyvitamin D3 33 have shown much lower calcemic effect and stronger cell differentiating ability than 1. In this paper, we reported synthesis of 19-nor-1(, 25-dihydroxy-22-oxo-vitamin …     

Total Synthesis of (±)-Nimbonone and (±)-12-Ethyl-13-methoxy- 8,11,13-podocarpatriene

Most diterpenoids exhibit significant bioactivities, such as antidermatophytic, antibact- erial, and antioxidant. Although a large number of aromatic tricyclic diterpenoids have been isolated, there are a few of them having ethyl substituent. The synthesis of this type diterpenoids has been seldom reported. In order to further study the relationship between the structure and bioactivities of the diterpenoid, we extended the diterpene synthesis1,2,3. It is desirable to report herein the syn…     

The First Total Synthesis of Isoliquiritin

Isoliquiritin 1 was isolated from the roots of G. uralensis and also from other plants, and has been reported to exhibit antitumour, anti-HIV, curing hepatitis activities1, 2, use as anti-allergic drug4, and for sweetening3. It has been used for a strong inhibitor of hyaluronidase4. HOOHOOGluc561'2'3'4'5'6'1243βα1 OHHOOHHHHOHHOHGluc=2"3"4"6"1"5" The synthesis of isoliquiritin (4-glucopyranoxy-2,4-dihydroxy chalcone) has not been reported, because there is no suitable synth…     

Construction of the Skeleton of Phthalascidin, Mechanism of the Formation of the Key Tricyclic Lactam Intermediate

Phthalascidin is a structurally simplified version of Et-743, which is a potent anti-tumor marine natural product isolated from Ecteinascidia turbinata. Its antiproliferative activity is greater than that of the agents taxol, camptothecin, adriamycin, mitomycin C, cisplatin, bleomycin, and etoposide by 1-3 orders of magnitude. An elegant synthesis of Et-743 and phthalascidin has been reported by E. J. Corey and co-workers1,2. As part of our continuing program, we have also engaged in dev…     

Asymmetric Induction of Chiral 1,1''''-Bis(oxazolinyl)ferrocenes as Ligands in Metal-Catalyzed Cyclopropanation and Diels-Alder Reactions

Bis(oxazoline) ligands1 have been successfully used in a variety of metal-catalyzed asymmetric reactions, such as cyclopropanation, allylic oxidation reactions, etc; Chiral ferrocene derivatives2 have also been proved as effective ligands in numerous asymmetric reactions, for example, chiral ferrocenylphosphines exhibited high enantioselectivity for the reduction of olefins, Heck reactions and Aldol reactions of aldehydes. These results stimulated us to study the behaviour the bis(oxazoline) …     

Regioselective Addition of Silyl Enolates to α, β-Unsaturated Aldehyde and its Acetal Catalyzed by MgI_2 Etherate

In our previous letter1, we have reported the unique catalytic reactivity of MgI2 etherate 1 in the chemoselective Mukaiyama-type aldol reactions of aryl or vinyl aldehyde and aldehyde acetals with silyl enolates. Aryl or alkyl a, b-unsaturated aldehydes (and their acetals) are particularly reactive in this catalytic addition reaction due to possibly the effective activation of the electron-rich carbonyl by highly oxyphilic Lewis acidic species, i.e. IMg+, in non-coordinative media (i.e. CH…     

PRODUCTION OF LIGHT ALKENES FROM CO AND/OR CO_2 HYDROGENATION OVER K-Fe-MnO/SILICALITE-2 CATALYST

High selectivity to light alkenes can be achieved from CO and CO_2hydrogenation over K-Fe-MnO/Si-2 catalyst.The alkene selectivity isinsensitive to reaction temperature for CO hydrogenation,while apparentlyincreases for CO_2 hydrogenation with raising reaction temperature.An increasein alkene selectivity is observed for both CO and CO_2 hydrogenation with GHSVrising,While a decrease with the elevation of reaction pressure for both CO/H_2and CO_2/H_2 reaction.A two-step mechanism is suggested forCO_2 hydrogenation to form hydrocarbons,by which the variations incontributions of CO and HC as products of CO_2/H_2 reaction with change ofreaction temperature,GHSV and pressure are explained.Moreover,thecatalyst is favorable for selective production of light olefins,which can alsoconcern the slightly secondary reactions of light olefins to some extent.     

Modification of Metal Complex on the StereoselectiveHydrogenation of 2,3-Butanedione

Nanoscopic metal clusters, because of their substantial difference from metal atoms and bulk metals in size and structure, have attracted great interest especially in the field of catalysis1. It is well known that additives can markedly affect the properties of metal catalysts. The effect of metal ions has been well studied in the field of heterogeneous catalysis2. However, the study of metal complex effect is scarce. We have reported that the metal complex can considerably modulate both the a…     

Synthesis and biological evaluation of 2,4-diaminopteridine derivatives as nitric oxide synthase inhibitor

A series of novel 2,4-diamino-pteridines(9a-1)were synthesized and evaluated as inhibitors of inducible nitric oxide synthase (iNOS)in vitro.It was found that 9a,9d,9e,9h,9i and 91 showed potent inhibitory activities similar to that of methotrexate(MTX),while the activities of 9b,9c,9f,9g,9j and 9k ale stronger than MTX.