Oxalyl chloride /DMF

Vilsmeier-Haack formylation of 2-(4-methyl-l-piperazinyl)-4//-pyrido-[l,2-n]pyrimidin-4-one with a mixture of POCI3 and DMF at 95°C gave a 3-formyl derivative (93FES1225) while ethyl 4-oxo-6,7,8, 9-tetrahydro-4//-pyrido[l,2-n]pyrimidine-2-acetate at 50 °C yielded a 9-dimethylaminomethylene-3-formyl derivative (01MI4). 3-Formyl-2-hydroxy-8-[2-(4-isopropyl-l,3-thiazol-2-yl)-l-ethenyl]-4//-pyrido[l,2-n]pyri-midin-4-one was obtained from the 3-unsubstituted derivative with oxalyl chloride-DMF reagent in CH2CI2 at room temperature for 3h (OlMIPl). 

Scheme 3.4 Reagents and conditions (a) oxalyl chloride, DMF (b) CH2N2, Et20, 76% over two steps (c) PhC02Ag (0.3 equiv), Et3N (6 equiv), MeOH, 0-25°C, 3h, 78%.

This ring may be constructed by annulating amino and carboxylic groups attached to different rings with oxalyl chloride-DMF or in a high-boiling solvent such as xylene. 

Reagents (i), p-TosCl, pyridine (ii), 4-chlorobutanenitrile, K2CO3, KI, 2-butanone (iii), r-BuOK, DMF (iv), AcOH, HCl (v), pyridinium hydrobromide perbromide, CHCI3 (vi), ethanimidamide monohydrochloride, K2CO3, CHCI3 (vii), H2SO4, AcOH (viii), 4-nitrobenzoyl chloride, DMF, pyridine monohydrochloride (ix), H2, Raney nickel, MeOH (x), biphenyl-2-carboxylic acid, oxalyl chloride, DMF, CH2CI2, MeCN, pyridine, HCl-AcOEt. 

Preparation of Phosphonic Acid Chlorides. Disilyl esters of phosphonic acids react with oxalyl chloride-DMF to give the phosphonyl chlorides and silyl chlorides under mild conditions (eq (>) Prior treatment of an acid-sensitive phosphonate monoester with Trimethylsilyldiethylamine was used to minimize exposure to HCl (eq 7). ... 

Aromatic compounds are formylated using triphosgene/DMF [1300], phosphorus oxychloride/DMF, or oxalyl chloride/DMF [1301],... 

An efficient synthesis of 2,4-dihydroxybenzaldehyde 1775 from resorcinol 1773 by a Vilsmeier-Haack reaction using either phosphorus oxychloride/DMF or oxalyl chloride/DMF, working below room temperature in acetonitrile, has been reported [1301]. 

Reaction schemes 257,258 and 259 gave some examples of some modes of formation of this important class of pyrethroids. The technical processes however, in order to obtain products as pure as possible, consists of the esterification of the acid chloride. Particularly sensible optically active acid chlorides may be obtained by chlorination with the system oxalyl chloride/DMF at lower temperatures [789]. In case of free cyanohydrine an acid scavenger is necessary [789 a], Alternatively, zinc chloride catalyzes the addition of an acid chloride to the aldehyde 280 to give the a-chlorobenzyl esters [790], which easily react with sodium cyanide [791] to give particularly clean products [792]. 

The Vilsmeier-Haack type adduct, formed by the reaction of oxalyl chloride with DMF can be also be employed for the activation of carboxylic acids, as shown in Fig. 8 [200]. 

Yet another method involves the treatment of a hemiacetal with oxalyl chloride in DMF. The protocol allows for an efficient preparation of a-chlorides of 2-deoxy-L-hexopyranosides (Scheme 2.28) [128]. 

Cyclization of the lithium enolate of the ketosulfone (iv) with 2,3-dichloroacrolein (xviii), obtained by treatment of 2-chloro-3-hydroxy-propenal (xv) with oxalyl chloride and DMF in toluene, followed by reaction with ammonium acetate or anhydrous ammonia... 

The Vilsmeier-Haack formylation procedure (Scheme 24) provides the most effective synthesis of formylpyrroles and indoles. Reaction of the heterocycles with the immonium cation (72), derived from DMF or (V-methylformanilide with an acid chloride, such as phosphorus oxychloride, thionyl chloride, phosgene, oxalyl chloride, benzoyl chloride or bromotriphenylphosphonium bromide, yields the intermediate heteroarylimmonium salt (73). Under suitable reaction conditions, this salt may be isolated from the reaction involving phosphorus oxychloride as an impure chlorophosphate (78TH30500) or precipitated from the reaction system as the thermally unstable perchlorate by the addition of sodium... 

A soln of a (—)-4-nitrobenzyl [cyclohexyl(Fmoc-amino)methyl]phosphonic add (57 40.0 mg, 0.073 mmol) in CH2C12 (2mL) was cooled to 0°C, and dry DMF (6pL, 0.01 mmol) and oxalyl chloride (13 pL, 0.147 mmol) were added. The mixture was stirred for 0.5 h at 0°C, diluted with benzene (5mL), and concentrated. The phosphonochloridate was redissolved in benzene (2mL), and treated with TEA (20 pL, 0.147 mmol) followed by AgCN (29 mg, 0.217 mmol). After 5 min at rt, D-2-hydroxy-3-(l//-indol-3-yl)propanamide (22.4mg, 0.011 mmol) was introduced, and the mixture was heated at reflux for 2h, cooled to rt, filtered, and concentrated. The phosphonate diester was purified via flash chromatography (2% MeOH/CH2Cl2) to give a mixture of diastereomers (19.8mg, 37%), which were separated by RP-HPLC. For the minor diastereomer (4.5 mg, amorphous solid) [a]D +15 (c 0.47, EtOH). 

RCOOH — RCHO. The iminium salt (1) formed on reaction of a carboxylic acid with the Vilsmeier reagent (formed from DMF and oxalyl chloride) is reduced by lithium tri-/-butoxyaluminum hydride (1 equiv.) to an aldehyde. The chemo-selectivity is noteworthy ester, nitrile, keto, and halide groups are not affected.3... 

Tetraethyl dimethylaminomethylenediphosphonate, 3, 277-278. The reagent can be prepared in 90% yield by reaction of the Vilsmeier reagent (from DMF and oxalyl chloride) with triethyl phosphite. 

In a flask flushed with nitrogen, the acid (5.5 eq, 2.34 mmol) and oxalyl chloride (3 ml, 6.02 mmol) were mixed in DCM (10 ml). One drop of DMF was added. The mixture was stirred for 1 h. The solvent and oxalyl chloride were then removed by evaporation. The acid choride was dissolved in 9 ml of a mixture of DCM and pyridine (9 1). Wang resin (loading 1.7 mmol/g) was added and the mixture was shaken overnight. The mixture was drained and the resin was washed with DMF, THF, DCM, and ether. The resin was dried overnight under reduced pressure. 

To a stirred solution of the methyl 2,3-di-0-benzyl-4-deoxy-a-D-glucopyranosiduronic acid (1.73 g, 4.65 mmol) in CH2CI2 (30 ml) was added oxalyl chloride (0.943 g, 0.65 ml, 7.43 mmol) followed by DMF (0.23 mmol) at room temperature. The resulting clear solution was stirred at room temperature for 2 h, and then concentrated in vacuo. 

To a stirred solution of the (+)-6-ethyl-5-methyl-3,6-dihydro-2H-pyran-2-carboxylic acid (3.0 g, 17.65 mmol) in CH2CI2 (60 ml), and DMF (0.12 ml) at 0°C was added oxalyl chloride (1.82 ml, 21.18 mmol) over a 30 min-period. The reaction mixture was stirred at 0°C for 1 h, then at room temperature for 2 h. The solvent was evaporated in vacuum, and the residue was used directly in the next reaction without further purification. In a 50 ml, two-necked, round-bottomed flask equipped with a Teflon-covered magnetic stirring bar, a drierite filled trap, and a thermometer was placed the crude acid chloride in HMPA (16 ml). Freshly prepared trans-propenyltrimethyltin (4.34 g, 21.18 mmol) was then added followed by the addition of... 

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