Showing papers by "Philip L. Fuchs published in 1994"
TL;DR: In this paper, amides and lactams were converted to their corresponding thioamides and thiolactams employing a new protocol using hexamethyldisilathiane (TMS 2 S).
Abstract: Amides and lactams were converted to their corresponding thioamides and thiolactams employing a new protocol using hexamethyldisilathiane (TMS 2 S). Oxophilic promoters mere employed to generate Vilsmeier-type intermediates, the most efficient reagents being phosphorus oxylchloride, triphosgene, and oxalyl chloride. Thionation of intermediate chloro iminium ions was accomplished in situ with TMS 2 S. Yields were good to excellent for secondary and tertiary amides and lactams while yields for primary systems mere poor
51 citations
33 citations
TL;DR: Tetramethylguanidinium azide was used in the quantitative conversion of glycosyl halides 1 - 5 to the corresponding gaseous azides 10 - 14 as discussed by the authors.
26 citations
TL;DR: The stereospecific synthesis of glycoprotein processing enzyme inhibitor (+) mannostatin A 1 was achieved in ten steps from D-ribonolactone 9 (∼ 39% overall yield) using methanesulfenyl triflate mediated intramolecular cyclization of allylic N-sufenylimidate 12.
21 citations
TL;DR: The Reich iodoso syn-elimination of iodide 18, Rhodium catalyzed intermolecular oxygen alkylation of secondary neopentyl alcohol 21, and Intramolecular Wadsworth-Emmons reaction to provide the ester precursor of aldehyde 4 as discussed by the authors.
20 citations
17 citations
TL;DR: In this article, a general route for the synthesis of methyl triflone derivatives utilizing triflic anhydride is described, and a deteroselective synthesis of E-vinyl and dienyl triflaminear derivatives has been accomplished by the Peterson olefination reaction of α-silyl triflinear anions.
16 citations
TL;DR: In this paper, an acid-catalyzed equilibration of spiroketals 55H ββ and 55H αβ involves a two-stage process whereby the 1,6-dioxaspiro[4.4]nonanes can be equilibrated under mild conditions to a pair of 1.5-decanes with preservation of the adjacent C-20 methyl stereocenter.
14 citations
14 citations
TL;DR: In this paper, the alkylation and conjugate-addition chemistry of γ-methoxy allylsulfonyl anions was used for the synthesis of homoharringtonine.
Abstract: Observations made during the synthesis of the anticancer agent homoharringtonine 37 have resulted in the development of several new synthetic methods based upon the alkylation and conjugate-addition chemistry of γ-methoxy allylsulfonyl anions. Enones, dienyl ketones, and trienyl ketones are readily constructed. Sultinium ion intermediates facilitate the sulfone to olefin transformation.
13 citations
TL;DR: In this article, the activation of α-glucosyl bromide in the presence of 2-trimethylsilylethyl sulfides as sulfur nucleophiles selectively provides β-thioglycosides.
TL;DR: Human platelets have been employed as an assay system to evaluate the pharmacological activity of a group of stable, arene-fused prostacyclin analogs and one compound in particular demonstrated these activities with potency similar to PGI2, i.e., competitive binding at the platelet prostacyClin receptor, elevation of intraplatelet cyclic AMP levels and inhibition of human platelet aggregation.
TL;DR: Several vinyl sulfone based substrates exhibited excellent in vitro activity against the HT-29 colon cancer cell line and also demonstrated in vitro differential cytotoxicity against ras transformed rat kidney epithelial cell lines.
TL;DR: Tetramethylguanidinium azide was used in the quantitative conversion of glycosyl halides 1 - 5 to the corresponding gaseous azides 10 - 14 as discussed by the authors.
Abstract: Tetramethylguanidinium azide was used in the quantitative conversion of glycosyl halides 1 – 5 to the corresponding glycosyl azides 10 – 14. The stereoselective reactions occurred with complete inversion at the anomeric centers. The titled reagent was also employed in the selective synthesis of pseudoglycosyl azide 16 and two steroidal azides 17 and 18. All reactions were carried out in non-halogenated solvents to avoid potential explosion hazards.
TL;DR: In this paper, amides and lactams were converted to their corresponding thioamides and thiolactams employing a new protocol using hexamethyldisilathiane (TMS 2 S).
Abstract: Amides and lactams were converted to their corresponding thioamides and thiolactams employing a new protocol using hexamethyldisilathiane (TMS 2 S). Oxophilic promoters mere employed to generate Vilsmeier-type intermediates, the most efficient reagents being phosphorus oxylchloride, triphosgene, and oxalyl chloride. Thionation of intermediate chloro iminium ions was accomplished in situ with TMS 2 S. Yields were good to excellent for secondary and tertiary amides and lactams while yields for primary systems mere poor
TL;DR: In this paper, the stereospecific synthesis of glycoprotein processing enzyme inhibitor (+) mannostatin A 1 was achieved in ten steps from D-ribonolactone 9 (∼ 39% overall yield).
Abstract: The stereospecific synthesis of glycoprotein processing enzyme inhibitor (+) mannostatin A 1 was achieved in ten steps from D-ribonolactone 9 (∼ 39% overall yield). The strategy featured methanesulfenyl triflate mediated intramolecular cyclization of allylic N-sufenylimidate 12.