Amino acid chloride hydrochlorides

Lyotropic liquid crystalline properties were observed for poly (arylamide) monodendrons derived from 1,3,5-substituted amino acid chloride hydrochlorides according to Kim [168]. These systems aggregate readily to form high molecular weight species in the absence of complexing ions. Amide solvents containing more than 40 wt.% of the dendrons exhibit nematic phase liquid crystalline texture under a polarizing microscope, whereas, 60 wt.% solutions produce a hard gel under static conditions. 

Amino carboxylic acids or their hydrochlorides, when treated with PC15 in acetyl chloride1089 or, better, in CC14 (which dissolves PC15)1090 give the amino acid chloride hydrochlorides. Since these salts are very sensitive to moisture, the reaction must be carried out in a closed apparatus and the product must be collected on a protected frit and finally washed with a suitable solvent (light petroleum or CC14) and sucked dry. 

When either or both of the comonomers has a functionality higher than 2, a branched system evolves. The major limitation of the Schotten-Baumann reaction is its uses of AA and BB-type monomers, to the exclusion of AB-type monomers. This is simply due to the general unavailability of AB-type monomers in which A is an acid chloride and B is a free amine. Responding to the need, a procedure was developed over the years at duPont by which a reactive AB-type monomer is first prepared and then reacted with itself to create linear [210, 414, 415] or highly branched [416] aromatic polyamide polymers. Accordingly, an amino acid chloride hydrochloride (e.g.,)... 

To a soln of amino acid ester hydrochloride (1 mmol) and KOBt (1 mmol) in CH2CI2 (3 mL) was added a soln of Fmoc amino acid chloride (1 mmol) and KOBt (1 mmol) in CH2CI2 (3 mL). The mixture was stirred for 3 h then washed with aq 5% NaHC03, 5% HCl, HjO, sat aq NaCl soln, and dried. The organic layer was concentrated and the residue recrystallized (CHjCyhexane) yields 70-80% (Table... 

Peptide synthesis. Sheehan and co-workers used this water-soluble reagent for a simplified and rapid synthesis of tetra- and pentapeptides without isolation of intermediates. The reagent (I. I equiv.) is added to a solution of the N-carbobenzoxy-amino acid (I equiv.), the amino acid ester hydrochloride or peptide ester hydrochloride (1 equiv.), and triethylamine (1 equiv.) in methylene chloride. After I hr. at room temperature the solution was washed successively with water (to remove excess reagent and the urea), dilute hydrochloric acid, and sodium bicarbonate solution. The curbobenzoxy group Is removed by hydrogenolysis and the product used directly in the next step. ... 

Reactions between A -(l-chloroalkyl)pyridinium chlorides 33 and amino acids in organic solvents have a low synthetic value because of the low solubility of the amine partner. A special protocol has been designed and tested in order to circumvent this drawback. Soon after the preparation of the salt, an aqueous solution of the amino acid was introduced in the reaction medium and the two-phase system obtained was heated under reflux for several hours. However, this was not too successful because sulfur dioxide, evolved during the preparation of the salt, was converted into sulfite that acted as an 5-nucleophile. As a result, A -(l-sulfonatoalkyl)pyridinium betaines such as 53 were obtained (Section IV,B,3) (97BSB383). To avoid the formation of such betaines, the salts 33 were isolated and reacted with an aqueous solution of L-cysteine (80) to afford thiazolidine-4-carboxylic acids hydrochlorides 81 (60-80% yields). 

A suspension of 37.3 g (0.1 mol) of 7/3-amino-3-methoxy-3-cephem-4-carboxylic acid hydrochloride dioxanate in 500 ml methylene chloride is stirred for 15 minutes at room temperature under an argon atmosphere and treated with 57.2 ml (0.23 mol) of bis-(trimethylsilyl)-acetamide. After 45 minutes the faintly yellow slightly turbid solution is cooled to 0°C and treated within 10 minutes with 31.2 g (0.15 mol) of D-Ct-amino-Ct-d, 4-cyclohexadienyl (acetyl chloride hydrochloride. Thirty minutes thereafter 15 ml (about 0.21 mol) of propylene oxide is added and the mixture is further stirred for 1 hour at 0°C. A cooled mixture of 20 ml of absolute methanol in 200 ml of methylene chloride is added within 30 minutes, after another 30 minutes the precipitate is filtered off under exclusion of moisture, washed with methylene chloride and dried under reduced pressure at room temperature. The obtained hygroscopic crystals of the hydrochloride of 7j3-[D-a-(1,4-cyclohexadienyl)acetylamino] -... 

The combined liquors, which comprise an aqueous hydrochloric acid solution of 3-amino-methyl-pyridine hydrochloride, are then heated to a temperature of 60° to 65°C, and ethyl nitrite gas is passed into the heated solution. The ethyl nitrite is generated by placing 20 liters of 90% ethyl alcohol in a suitable vessel, diluting with 200 liters of water, and, while stirring, adding to the dilute alcohol 18.3 kg of nitrosyl chloride at the rate of 2.25 kg per hour. (The process using methyl nitrite is carried out by substituting a stoichiometrically equivalent quantity of methyl alcohol for the ethyl alcohol.)... 

Malonic acid, amino-, diethyl ester, HYDROCHLORIDE, 40, 24 Malonic acid, bts(hydroxymethyl)-, DIETHYL ETHER, 40, 27 Malonitrile, condensation with tetra-cyanoethylene, 41, 99 2-Mercaptopyrimidine, 43, 6S hydrochloride of, 43, 68 Mercuric oxide in preparation of bromo-cyclopropane, 43, 9 Mesityl isocyanide, 41,103 5-Methallyl-l,2,3,4,5-pentachlorocyclo-pentadiene, 43, 92 Methane, dimesityl-, 43, 57 Methanesiileinyl chloride, 40, 62 Methanesulfonic acid, solvent for making peroxybenzoic acid from benzoic acid, 43, 93... 

D(-)-2-(4-hydroxyphenyl)glycyl chloride hydrochloride see under D-/ -hydroxyphenylglycyl chloride hydrochloride 7-hydroxy-7-phenylheptanoic acid (CijHigOi 103187-18-4) see Seratrodast [/ -(/J, S )]-[2-hydroxy-l-[[(phenylmethoxy)amino]carbo-nyl]propyl]carbamic acid l,l carbonyl]amino]hep-tanoic acid... 

Trichloromethyl chloroformate has proven effective in the preparation of N-carboxy-a-amino acid anhydrides from amino acids, and various compounds having isocyanate, acid chloride, and chloroformate groups.For example, trichloromethyl chloroformate may be used instead of phosgene in the preparation of 2-tert-butoxycarbonyloxyimino-2-phenylacetonitrile. The use of this reagent is illustrated here by the synthesis of 3-isocyanato-propanoyl chloride from 3-aminopropanoic acid hydrochloride. 

Chloroprocaine Chloroprocaine, the 2-diethylaminoethyl ester of 2-chloro-4-aminoben-zoic acid (2.1.5), is the ortho-chlorinated (in relation to the carbonyl group of the benzene ring) analog of procaine. Synthesis of this drag is accomplished by directly reacting the hydrochloride of the 4-amino-2-chlorbenzoic acid chloride (2.1.4) with hydrochloride of diethylaminoethanol. The hydrochloride of 4-amino-2-chlorbenzoic acid chloride needed for synthesis is synthesized by reacting 2-chloro -aminobenzoic acid with thionyl chloride [5],... 

A solution of 50 mmol of the hydrochloride of the amino acid ethyl ester 5 is dissolved in 100 mL of ethanol and added during 1 h to 100 mL of 8M methanamine in ethanol at 0 C. After 4 h the mixture is allowed to reach 20 CC and stirred at that temperature for 30 h. 300 mL of diethyl ether is added, the mixture is cooled to — 20 JC and the methylammonium chloride is filtered off. The solvents are evaporated off under vacuum and the residue is dissolved in 40 mL of CH2C12, recooled to — 20 °C and additional precipitated methylammonium chloride is filtered off. After evaporation of the solvent the residual A-methylamide is sufficiently pure to use in the next step without further purification. 

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