Dichloromethane, hydrolysis

Similarly, the methiodide was reacted with diethyl (2,2,2-trichloro-ethoxycarbonyl)aminomalonate as a nucleophile to give 118, which was then converted to the amine 119 by deprotection of the 2,2,2-trichloroethoxy-carbonyl group with zinc and potassium dihydrogen phosphate. Dehydrative cyclization of 119 to the azepinoindole 120 was achieved by heating 119 in the presence of a catalytic amount of pyridinium p-toluenesulfonate in dichloromethane. Hydrolysis of 120 with potassium hydroxide in methanol yielded the malonic acid derivative which was then readily decarboxylated on heating in aqueous ethanol to accomplish total syntheses of ( )-cis- and ( )-tranj-clavicipitic acid (84,85) in aratio 3 2 (Scheme 18) (57). 

Forsyth et al. [96] have recently used Au(I)-catalyzed spirocycUzations for the synthesis of both spiroacetal fragments of okadaic acid 176 (Scheme 41). Synthesis of the C15-C27 spiroacetal was accomplished by treating alkyne 171 with catalytic AuCl in dichloromethane. Hydrolysis of the PMP-acetal then afforded 172 in high yield over two steps. 

Of the alkyl esters, methyl esters are the most useful because of their rapid hydrolysis. The acid is refluxed with one or two equivalents of methanol in excess alcohol-free chloroform (or dichloromethane) containing about O.lg of p-toluenesulfonic acid (as catalyst), using a Dean-Stark apparatus. (The water formed by the... 

Chloro-l//-l-benzazepines 2 are obtained as unstable red oils in excellent yields by heating 1 //-l-benzazepin-2(3//)-ones 1 with phosphoryl chloride in pyridine.208 Reaction conditions are important since in the absence of pyridine, or in dichloromethane solution, only poor yields of dimers, e.g. 3, are produced. The chlorobcnzazepines are stable for only short periods (24 hours in anhydrous pyridine) and rapidly polymerize. Isolation of the pure chloro compounds is difficult since they undergo very rapid hydrolysis to the benzazepinones. 

Chiral imines derived from 1-phenylethanone and (I. Sj-exo-l, 7,7-trimethyIbicyclo-[2.2.1]heptan-2-amine [(S)-isobornylamine], (.S>1-phenylethanamine or (R)-l-(1-naphthyl) ethanamine are transformed into the corresponding (vinylamino)dichloroboranes (e.g., 3) by treatment with trichloroborane and triethylamine in dichloromethane. Reaction of the chiral boron azaenolates with aromatic aldehydes at 25 "C, and subsequent acidic hydrolysis, furnishes aldol adducts with enantiomeric excesses in the range of 2.5 to 47.7%. Significantly lower asymmetric inductions are obtained from additions of the corresponding lithium and magnesium azaenolates. Best results arc achieved using (.S )-isobornylamine as the chiral auxiliary 3. 

Chloroform is more rapidly hydrolyzed with base than dichloromethane or carbon tetrachloride and gives not only formic acid but also carbon monoxide Hine has shown that the mechanism of chloroform hydrolysis is quite different from that of dichloromethane or carbon tetrachloride, though superficially the three reactions appear similar. The first step is the loss of a proton to give CCla , which then loses Cl to give dichlorocarbene CCI2, which is hydrolyzed to formic acid or carbon monoxide. 

Isolated yield. A, CFjOF in CCI3F at — 60 to — 80° with or without CaO B, F2 in Ar (or N2—CCI3F) at — 78° B, F2 in N2—HjO at room temperature C, Xep2-BF3 OEt2 in ether, benzene, toluene, dichloromethane, or a mixture of some of them (0° to room temperature). Yield of the deprotected compound after hydrolysis. " 2,2-Difluoro compound, Estimated from the final 2-deoxy-2-fluoroglycose. 

Metabolites may also play a role in the association of the substrate with humic and fulvic acid components. Two illustrations are given (a) naphth-l-ol, an established fungal metabolite of naphthalene, may play a role in the association of naphthalene with humic material (Burgos et al. 1996) and (b) it has been shown that C-labeled metabolites of [9- C]-anthracene including 2-hydroxyanthracene-3-carboxylate and phthalate were not extractable from soil with acetone or dichloromethane, and required alkaline hydrolysis for their recovery (Richnow et al. 1998). 

Acetochlor and its metabolites are extracted from plant and animal materials with aqueous acetonitrile. After filtration and evaporation of the solvent, the extracted residue is hydrolyzed with base, and the hydrolysis products, EMA and HEMA (Figure 1), are steam distilled into dilute acid. The distillate is adjusted to a basic pH, and EMA and HEMA are extracted with dichloromethane. EMA and HEMA are partitioned into aqueous-methanolic HCl solution. Following separation from dichloromethane, additional methanol is added, and HEMA is converted to methylated HEMA (MEMA) over 12 h. The pH of the sample solution is adjusted to the range of the HPLC mobile phase, and EMA and MEMA are separated by reversed phase HPLC and quantitated using electrochemical detection. 

In water (pH 7), 6mgL i (20°C). Low solubility in hexane, n-octanol moderate solubility in methanol, toluene, acetone high solubility in ethyl acetate, acetonitrile, dichloromethane Stable to aqueous hydrolysis... 

Attempted Hydrolysis of S-b-MM with KOH. A solution of S-b-MM-90/10-wt (1.50 g, 1.5 meq MM) in 1 9 water-THF (50 mL) was treated with KOH (1.57 g, 28.0 mmol), and the mixture was refluxed for 47 hr. The solvents were evaporated, and the residue was shredded in a blender containing 200 mL of water. The solids were filtered, washed with water and methanol, and dried. The dried polymer was dissolved in dichloromethane and precipitated from methanol. The precipitate was washed with methanol and dried in a vacuum oven, yielding 1.23 g of product. Both 1H NMR and IR indicate essentially unreacted S-b-MM. 

Dining an attempt to prepare an anhydrous 25% solution of peroxyacetic acid in acetic acid by dehydrating a water-containing solution with acetic anhydride, a violent explosion occurred. Mistakes in the operational procedure allowed heated evaporation to begin before the anhydride had been hydrolysed. Acetyl peroxide could have been formed from the anhydride and peroxyacid, and the latter may have detonated and/or catalysed violent hydrolysis of the anhydride [1], A technique for preparing the anhydrous acid in dichloromethane without acetyl peroxide formation has been described [2],... 

Other electrophilic substitution reactions on aromatic and heteroaromatic systems are summarized in Scheme 6.143. Friedel-Crafts alkylation of N,N-dimethyl-aniline with squaric acid dichloride was accomplished by heating the two components in dichloromethane at 120 °C in the absence of a Lewis acid catalyst to provide a 23% yield of the 2-aryl-l-chlorocydobut-l-ene-3,4-dione product (Scheme 6.143 a) [281]. Hydrolysis of the monochloride provided a 2-aryl-l-hydroxycyclobut-l-ene-3,4-dione, an inhibitor of protein tyrosine phosphatases [281], Formylation of 4-chloro-3-nitrophenol with hexamethylenetetramine and trifluoroacetic acid (TFA) at 115 °C for 5 h furnished the corresponding benzaldehyde in 43% yield, which was further manipulated into a benzofuran derivative (Scheme 6.143b) [282]. 4-Chloro-5-bromo-pyrazolopyrimidine is an important intermediate in the synthesis of pyrazolopyrimi-dine derivatives showing activity against multiple kinase subfamilies (see also Scheme 6.20) and can be rapidly prepared from 4-chloropyrazolopyrimidine and N-bromosuccinimide (NBS) by microwave irradiation in acetonitrile (Scheme... 

Dimethylaminoethane-2-ol (20) is a compound that, by virtue of its nucleophilic center (Me2NH+C2H40), is employed to convert protected segments bound to supports as benzyl esters into acids by transesterification into dimethylaminoethyl esters [C(=0)0C2H4NMe2] that are hydrolyzable by a dimethylformamide-water (1 1) mixture. Compound 20 readily forms esters from acid chlorides. The hydrolysis and esterification are facilitated by anchimeric assistance by the adjacent nitrogen atom (see Section 2.10). The amino alcohol also reacts with dichloromethane. 

Phosphorylation of phenolate anions with dimethyl phosphorochloridothionate in water-dichloromethane systems normally gives large amounts of dithiopyrophos-phate because of extensive hydrolysis of the phosphorus chloride, but in the presence of tetrabutylammonium salts and 1 % imidazole, phosphorylation of the phenolate anion is complete. The explanation lies in an evident combination of activation of acylating agent (by imidazole) and of nucleophile (by phase-transfer catalysis).71... 

The reaction of dichloromethane (or its dideuterio derivative) (430) with lithium and a catalytic amount of DTBB (5%) in the presence of a carbonyl compound as electrophile in THF at —40 °C led, after final hydrolysis with water, to the corresponding 1,3-diols... 

For a recovery of (S)-a,a-diphenylprolinol, which is the hydrolysis product of the CBS-catalyst (S)-5 (and likewise its synthetic precursor ), the aqueous phase is carefully adjusted to pH 10 with concentrated ammonia and extracted with diethyl ether (3 x 50 ml). The combined organic layers are washed with brine (50 mL) and dried over MgS04. Removal of the solvent by rotary evaporation yields 1.68 g (79%) of crude (S)-a,a-diphenylprolinol. This material is dissolved in dichloromethane / methanol 9 1 (3 ml) and filtered over Alox B (act. Ill, 80 g) with dichloromethane / methanol 9 1 as the eluent, to yield 1.64 g (77%) of (S)-a,a-diphenylprolinol as a white solid. 

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