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1.
Limanto J Desmond RA Gauthier DR Devine PN Reamer RA Volante RP 《Organic letters》2003,5(13):2271-2274
Nucleophilic displacement of readily available alpha,alpha-dibromoketones with excess morpholine gave the corresponding ketoaminals, which upon condensation with aminoguanidine in MeOH in the presence of AcOH afforded 5-substituted-3-amino-1,2,4-triazines in >95% regioselectivity and 45-76% isolated yield. [reaction: see text] 相似文献
2.
Sergio Pinheiro Ronaldo C. da Silva Júnior José Walkimar de M. Carneiro O.A.C. Antunes 《Tetrahedron letters》2009,50(20):2402-962
Short stereoselective syntheses of both 5-substituted-4-amino-pyrrolidin-2-ones and 5-substituted-4-amino-3-pyrrolin-2-ones from natural α-amino acids are described. 相似文献
3.
A convenient method for the preparation of 5-methoxy-6-substituted-3-sulfonyl-delta-enlactams via regioselective nucleophilic addition to 5-methoxy-3-sulfonyl glutarimide is described. Formal syntheses of L-733,060, CP-99,994, and cassine are also reported. 相似文献
4.
The reaction of tricarbonyl (4-methoxy-1-methylcyclohexadienyl)iron hexafluorophosphate (1) with the keto ester nucleophile 5 to give complexes 6 and 7, and conversion of 6 in eight steps, via the enone 8a, to a D-homosteroid 11 is described. 相似文献
5.
Diversified 1,4,5-substituted-2-aminoimidazoles were rapidly assembled via sequential N–H insertion and Grignard addition to α-diazoesters. Lead compounds were identified as antibiotics against Gram-positive bacteria with an MIC value as low as 2 μg/mL. 相似文献
6.
Controlled base hydrolysis of one or both of the protected 1,2-dithiolene chelates of 1,3,5,7-tetrathia- s-indacene-2,6-dione (OCS 2C 6H 2S 2CO) enables the stepwise synthesis of di- and trimetallic complexes with 1,2,4,5-benzenetetrathiolate as the connector. Treatment of OCS 2C 6H 2S 2CO with MeO (-), followed by [NiBr 2(dcpe)] [dcpe = 1,2-bis(dicyclohexylphosphino)ethane], yields [(dcpe)Ni(S 2C 6H 2S 2CO)] ( 4). The reaction of 4 with EtO (-), followed by [MX 2(dcpe)] (X = halide), yields [(dcpe)Ni(S 2C 6H 2S 2)M(dcpe)] [M = Ni ( 5a), Pd ( 5b)]. Deprotection of the 1,3-dithiol-2-one group of 4, followed by introduction of (1)/ 2 equiv of MX 2 and then I 2, yields the neutral trimetallic compounds [(dcpe)Ni(S 2C 6H 2S 2)] 2M [M = Ni ( 6a), Pt ( 6b)]. Tetrahedralization at nickel is observed in 5a, which density functional theory calculations attribute to second-order Jahn-Teller effects, while 6a and 6b display an end-to-end folding of approximately 46 degrees . A color darkening is observed in moving from 4 to compounds 6 due to the increasing size of the conjugated metal-organic pi system. Intense, broad absorptions in the near-IR are observed for 6a and 6b. 相似文献
7.
A convergent synthesis of the key synthetic intermediate of hemibrevetoxin B was achieved via the intramolecular allylation of an α-chloroacetoxy ether and subsequent ring-closing metathesis. 相似文献
8.
[structure: see text] The antiviral agent (+/-)-virantmycin has been synthesized from two simple building blocks (2 and 3) in eight steps, as outlined in Scheme 2. 相似文献
9.
A concise approach to 5-substituted-4-pyrones is described. This approach is based on manipulation of the 5-hydroxy group of readily available kojic acid. A number of 5-substituted-4-pyrones were synthesized from kojic acid utilizing Heck reaction, Suzuki coupling and Stille coupling. 相似文献
10.
Taoues Temal-La?b Jacqueline Chastanet Jieping Zhu 《Journal of the American Chemical Society》2002,124(4):583-590
A general strategy for the synthesis of cyclopeptide alkaloids containing an endocyclic aryl-alkyl ether bond has been developed featuring a key intramolecular S(N)Ar reaction. The importance of the N-terminal protective group in the realization of such a strategy is documented. From the appropriate amino acid constituents, the natural sanjoinine G1, a 14-membered para cyclophane, has been synthesized in seven steps with 21% overall yield. 相似文献
11.
A KrishnaiahB Narsaiah 《Journal of fluorine chemistry》2002,115(1):9-11
The 3-cyano-4-trifluoromethyl-6-phenyl or substituted phenyl 2(1H) pyridones (1) on reaction with hydrazine hydrate, gave exclusively in 5-trifluoromethyl-3-substituted pyrazoles (3) through a novel method. A possible mechanistic pathway for change in the site of nucleophilic attack due to the CF3 group in 2(1H) pyridones is described. 相似文献
12.
Richard D. Chambers Brian Grievson Frederick G. Drakesmith Richard L. Powell 《Journal of fluorine chemistry》1985,29(3):323-339
Fluorinations of the free-radical adducts of fluorinated alkenes, to ethers, over cobalt trifluoride are described and perfluorinated ethers are obtained at temperatures in excess of 400°C. The effect of structure on the formation of perfluoroethers is outlined. 相似文献
13.
Shuai Zhao 《Journal of fluorine chemistry》2010,131(5):597-605
A general procedure for the preparation of 4-substituted-3-halo-2-quinolones (halo = F, Cl, Br) utilizing 2-halo diethylphosphonoacetic acids (halo = F, Cl, Br) and o-aminophenylketones as the starting materials is described. The title compounds are obtained by an intramolecular Horner-Wadsworth-Emmons olefination of halogen-containing N-acyl-o-aminophenylketones. The transformation process is generally applicable under mild conditions. 相似文献
14.
É. S. Krichevskii O. B. Romanova A. N. Grinev 《Chemistry of Heterocyclic Compounds》1983,19(12):1302-1305
Bromination of 2-methyl-3-phenyl-5-nitroindoles has given previously unknown 2-bromoethyl-3-phenyl-5-nitroindoles, which were converted by the Delepine reaction into 2-aminomethyl-3-phenyl-5-nitroindoles. One of these (1-methyl-2-aminomethyl-3-phenyl-5-nitroindole) was also obtained by reductive amination of 1-methyl-2-formyl-3-phenyl-5-nitroindole by the Leuckart-Wallach reaction. 相似文献
15.
[reaction: see text] An effective strategy has been developed for the rapid and efficient one-pot synthesis of 2-aryl-5-substituted-2,3-dihydrobenzofurans from readily available o-nitrotoluenes and aromatic aldehydes. This strategy allows access to a structurally diverse array of products for further manipulation. 相似文献
16.
Kandasamy Ramasamy Roland K. Robins Ganapathi R. Revankar 《Journal of heterocyclic chemistry》1988,25(3):1043-1046
4-Amino-7-(2,3,5-tri-O-benzyl-β-D-arabinofuranosyl)pyrrolo[2,3-d]pyrimidine-5-carbonitrile ( 6a ), prepared from 2-ethoxymethyleneamino-5-bromopyrrole-3,4-dicarbonitrile ( 4 ), was debenzylated with boron trichloride to give ara-toyocamycin ( 6b ). Further functional group transformation of 6b provided a route to 4-amino-7-β-D-arabinofuranosylpyrrolo[2,3-d]pyrimidine-5-thiocarboxamide (ara-thiosangivamycin, 7a ), and the corresponding 5-carboxamidoxime 8a and 5-carboxamidine 8b derivatives. Phosphorylation of unprotected 7a with phosphorus oxychloride gave ara-thiosangivamycin 5′-monophosphate ( 7b ). 2′-O-Acetyl-ara-thiosangivamycin ( 10b ) was prepared as a prodrug by acetylation of 9a , followed by deprotection of the t-butyldimethylsilyl groups under acidic conditions without acyl migration. 相似文献
17.
18.
3β-取代-5-甾烯-17-酮与碳酸二甲酯经克莱森缩合所得产物再分别与肼或羟胺反应,合成了几种新的△5-3β-取代-5-甾烯并-1'-取代[17,16-c]吡唑啉-5'-酮和△5-3β-取代-5-甾烯并[17,16-c]异噁唑啉-5'-酮化合物,其结构均经元素分析,IR和1H NMR确证. 相似文献
19.
[reaction: see text] A cyclopropanol fragmentation approach to the synthesis of oxepanes has been developed. This convergent strategy condenses cyclopropyl diols with aldehydes to form an acetal, which is subsequently rearranged to furnish a keto-oxepane. The reaction has been developed as a one-pot procedure, utilizing sequential addition of Al(OTf)3 and TiCl4. Yields range from 50 to 70% for the sequence. A Zimmerman-Traxler transition state disposing substituents in equatorial positions is consistent with the observed formation of strictly cis products. 相似文献
20.
[structure: see text]. A novel stereoselective approach to the ring system of the mitomycins is described. The synthesis was based on a convergent strategy involving a stereocontrolled addition of a beta-phenyl silyl enol ether to a pyrroline N-acyliminium ion followed by an intramolecular palladium-catalyzed aryl triflate amination to afford the (9R*,9aR*)-tetrahydropyrrolo[1,2-a]indole ring system. 相似文献