N,0-Dimethylhydroxylamine

The reaction of 6-methylpyridine-3-carboxylic acid methyl ester with N,0-dimethylhydroxylamine and isopropyl-magnesium chloride in toluene gives the N-methoxyamide derivative (x), which is reduced with diisobutyl aluminium hydride (DIBAL) to afford 6-methylpyridine-3-carbaldehyde (xi). The reaction of the aldehyde (xi) with a phosphite provides the diphenyl phosphonate derivative, which is condensed with 4-(methylsulfonyl)benzaldehyde in the presence of potassium fe/f-butoxide in HF to yield the enimine (xii). Finally, this compound is hydrolyzed with HCI to yield the ketosulfone (ix). 

Chloro-2,8-bis(trifluoromethyl)quinoline N,0-Dimethylhydroxylamine hydrochloride Benzyltriethylammonium chloride Sodium hydroxide... 

Dimethyl 3,3a,3b,4,6a,7a-hexahydro-3,4,7-metheno-7H-cyclopenta[a]pentalene-7,8-dicarboxylate 3,4,7-Metheno-7H-cyclopenta[a]pentalene-7,8-dicarboxylic acid, 3,3a,3b,4,6a,7a-hexahydro-, dimethyl ester (53282-97-6), 68, 198 Dimethyl (E)-2-hexenedioate (70353-99-0), 66, 52, 53, 59 N,0-Dimethylhydroxylamine hydrochloride Methylamine, N-methoxy-, hydrochloride Methanamine, N-methoxy-, hydrochloride (6638-79-5), 67, 69 N,N-Dimethylisobutyramide, 66, 117, 118... 

The product from Step 5 (28.5 mmol) was initially converted into the acid chloride by reacting with 5 ml oxalyl chloride then added to a suspension of N,0-dimethylhydroxylamine chloride (5.6 g) in a mixture of CH2CI2 and water containing Na2C03 (3 g). The protected acid was isolated as a pale yellow solid. 

Treatment of tricarboxylic acids with HaNOBz HCl in the presence of EDC affords the corresponding trishydroxamic acids. Reaction of carboxylic acids with N,0-dimethylhydroxylamine 569, using DCC, affords the expected hydroxamic acid derivatives 570. " ... 

Boa-L-Leuoine N-msthyl-O-methyloarboxamide. A 1-L, three-necked, round-bottomed flask is equipped with a mechanical stirrer, an electronic digital thermometer, and a graduated addition funnel. The flask is charged with 39.1 g (0.4 mol) of N,0-dimethylhydroxylamine hydrochloride (Note 1) and 236 mL of methylene chloride (Note 2). The suspension is stirred and cooled to 2°C with an ice-water bath. N-Methylpiperidine (Note 3), 48.8 ni. (0.41 mol), is placed in the addition funnel and added dropwise while the temperature is maintained at 2° + 2°C. A clear, colorless solution results which is kept cold and used in the following reaction. 

N,0-Dimethylhydroxylamine hydrochloride was obtained from the Aldrich Chemical Company, Inc., and used as received. 

N,0-Dimethylhydroxylamine hydrochloride Methylamine, N-methoxy-, hydrochloride (8) Methanamine, N-methoxy-, hydrochloride (9) (6638-79-5) N-Methylpiperidine Piperidine, l-methy1- (8,9) (626-67-5) N-tert-Butoxycarbonyl-L-leucine hydrate Leucine, N-carboxy-, N-tert-butyl ester, L- (8) L-Leucine, N-[(l,l-dimethylethoxy)carbonyl]- (9) (13139-15-6)... 

The requisite W-methoxy-N-methylamides may be prepared from acid chlorides by employing a slight excess of the commercially available N,0-dimethylhydroxylamine hydrochloride in the presence of pyridine. They have also bMn prepared from acylimidazoles and from mixed anhydrides of carboxylic acids. Once prepared, these systems possess stability equivalent to that of most tertiary amides and, in... 

The reagent 1292 can be conveniently prepared in 94% yield by the addition of N,0-dimethylhydroxylamine hydrochloride 1291 and triethylamine to a solution of di-2-pyridyl carbonate (DPC) in dichloromethane at 0 °C. It is easily separated by aqueous work-up (2-hydroxypyridine is very soluble in water) and purified by column chromatography on silica gel or kugelrohr vacuum distillation (bp 116-120 °C/0.20 mmHg). This phosgene equivalent shows no sign of decomposition when kept for two months in a refrigerator. 

Typical procedure. p-Methoxyvalerophenone 1294k [963] Preparation of N-Methoxy-N-methyI-2-pyridyI urethane 1292 To a solution of di-2-pyridyl carbonate (2.162 g, 10 mmol) in dichloromethane (30 mL), N,0-dimethylhydroxylamine hydrochloride 1289 (975.5 mg, 10 mmol) and triethylamine (1.42 mL, 10.2 mmol) were added at 0 °C. After stirring for 1 h at 0 °C, the reaction mixture was allowed to warm to room temperature over a period of 1 h. It was then poured into saturated aq. NaHCOj solution (60 mL) and the aqueous phase was extracted with dichloromethane (3 X 30 mL). The combined organic extracts were dried over MgS04, filtered, and concentrated to dryness in vacuo. The crude product was purified by... 

Activation of Carboxylic Acids as Mixed Anhydrides. Activation of A-(alkoxycarbonyl)-a-amino acids as mixed anhydrides using MCF/(V-methylpiperidine in CH2CI2 minimizes urethane byproduct formation and racemization during peptide bond formation. Reaction of these mixed anhydrides with N,0-Dimethylhydroxylamine followed by LiAlHq reduction provides an attractive route to the corresponding (V-(alkoxycarbonyl)-a-amino aldehydes (eq 13). Attempts to generate mixed anhydrides from iV-acyl-oe-amino... 

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