- Cobalt-Catalyzed Deoxygenative Hydroboration of Nitro Compounds and Applications to One-Pot Synthesis of Aldimines and Amides
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The commercially available and bench-stable Co(acac)2 ligated with bis[(2-diphenylphosphino)phenyl] ether (dpephos) was employed for selective room temperature hydroboration of nitro compounds with HBPin (TOF up to 4615 h?1), tolerating halide, hydroxy, amino, ether, ester, lactone, amide and heteroaromatic functionalities. These reactions offered a direct access to a variety of N-borylamines RN(H)BPin, which were in situ treated with aldehydes and carboxylic acids to produce a series of aldimines and secondary carboxamides without the need for dehydrating and/or coupling reagents. Combination of these transformations in a sequential one-pot manner allowed for direct and selective synthesis of aldimines and secondary carboxamides from readily available and inexpensive nitro compounds.
- Gudun, Kristina A.,Hayrapetyan, Davit,Khalimon, Andrey Y.,Segizbayev, Medet,Slamova, Ainur,Zakarina, Raikhan
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- Hydrosilylative reduction of primary amides to primary amines catalyzed by a terminal [Ni-OH] complex
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A terminal [Ni-OH] complex1, supported by triflamide-functionalized NHC ligands, catalyzes the hydrosilylative reduction of a range of primary amides into primary amines in good to excellent yields under base-free conditions with key functional group tolerance. Catalyst1is also effective for the reduction of a variety of tertiary and secondary amides. In contrast to literature reports, the reactivity of1towards amide reduction follows an inverse trend,i.e., 1° amide > 3° amide > 2° amide. The reaction does not follow a usual dehydration pathway.
- Bera, Jitendra K.,Pandey, Pragati
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supporting information
p. 9204 - 9207
(2021/09/20)
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- Green method for catalyzing reduction reaction of aliphatic nitro derivative
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The invention relates to a green method for catalyzing reduction reaction of aliphatic nitro derivatives. According to the method, non-transition metal compounds, namely triethyl boron and potassium tert-butoxide, are used as a catalytic system for the first time, an aliphatic nitro derivative and pinacolborane which is low in price and easy to obtain are catalyzed to be subjected to a reduction reaction under mild conditions, and an aliphatic amine hydrochloride product is synthesized after acidification with a hydrochloric acid aqueous solution. Compared with a traditional method, the method generally has the advantages that the catalyst is cheap and easy to obtain, operation is convenient, and reaction is safe. The selective reduction reaction of the aliphatic nitro derivative catalyzed by the non-transition metal catalyst and pinacol borane is realized for the first time, and the aliphatic amine hydrochloride product is synthesized through acidification treatment of the hydrochloric acid aqueous solution, so that a practical new reaction strategy is provided for laboratory preparation or industrial production.
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Paragraph 0005-0006; 0009-0012
(2021/07/31)
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- Transition metal-free catalytic reduction of primary amides using an abnormal NHC based potassium complex: Integrating nucleophilicity with Lewis acidic activation
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An abnormal N-heterocyclic carbene (aNHC) based potassium complex was used as a transition metal-free catalyst for reduction of primary amides to corresponding primary amines under ambient conditions. Only 2 mol% loading of the catalyst exhibits a broad substrate scope including aromatic, aliphatic and heterocyclic primary amides with excellent functional group tolerance. This method was applicable for reduction of chiral amides and utilized for the synthesis of pharmaceutically valuable precursors on a gram scale. During mechanistic investigation, several intermediates were isolated and characterized through spectroscopic techniques and one of the catalytic intermediates was characterized through single-crystal XRD. A well-defined catalyst and isolable intermediate along with several stoichiometric experiments, in situ NMR experiments and the DFT study helped us to sketch the mechanistic pathway for this reduction process unravelling the dual role of the catalyst involving nucleophilic activation by aNHC along with Lewis acidic activation by K ions.
- Bhunia, Mrinal,Sahoo, Sumeet Ranjan,Das, Arpan,Ahmed, Jasimuddin,Sreejyothi,Mandal, Swadhin K.
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p. 1848 - 1854
(2020/03/03)
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- Hydrosilane Reduction of Nitriles to Primary Amines by Cobalt-Isocyanide Catalysts
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Reduction of nitriles to silylated primary amines was achieved by combination of 1,1,3,3-tetramethyldisiloxane (TMDS) as the hydrosilane and a catalytic amount of Co(OPIV)2 (PIV = COtBu) associated with isocyanide ligands. The resulting silylated amines were subjected to acid hydrolysis or treatment with acid chlorides to give the corresponding primary amines or imides in good yields. One-pot synthesis of primary amides to primary amines with hydrosilanes was also achieved by iron-cobalt dual catalyst systems.
- Sanagawa, Atsushi,Nagashima, Hideo
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supporting information
p. 287 - 291
(2019/01/10)
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- Liquid-phase hydrogenation of nitriles to amines facilitated by a co(ii)/zn(0) pair: a ligand-free catalytic protocol
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The given report introduces a simple and user-friendly in situ method for the production of catalytically active cobalt particles. The approach circumvents the use of air-and moisture-sensitive reductants as well as the application of anhydrous Co-precursor salts. Accordingly, the described catalytic system is readily assembled under open-flask conditions by simply combining the components in the reaction vessel. Therefore, the arduous charging procedure of the reaction autoclave in a glovebox under an inert gas atmosphere is no longer necessary. In fact, the catalytically active material is obtained upon treatment of readily available Co(OAc)2·4 H2O with benign commercial Zn powder. The catalytic performance of the resultant material was tested in the heterogeneous hydrogenation of nitriles to the corresponding primary amines. Both activity and selectivity of the cobalt catalyst are significantly enhanced if a triflate-based Lewis acid and ammonia is added to the reaction mixture.
- Timelthaler, Daniel,Topf, Christoph
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p. 11604 - 11611
(2019/10/02)
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- Selective Hydrogenation of Nitriles to Primary Amines Catalyzed by a Polysilane/SiO2-Supported Palladium Catalyst under Continuous-Flow Conditions
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Hydrogenation of nitriles to primary amines with heterogeneous catalysts under liquid-phase continuous-flow conditions is described. Newly developed polysilane/SiO2-supported Pd was found to be an effective catalyst and various nitriles were converted into primary amine salts in almost quantitative yields under mild reaction conditions. Interestingly, a complex mixture was obtained under batch conditions. Lifetime experiments showed that this catalyst remained active for more than 300 h (TON≥10 000) without loss of selectivity and no metal leaching from the catalyst occurred. By using this continuous-flow hydrogenation, synthesis of venlafaxine, an antidepressant drug, has been accomplished.
- Saito, Yuki,Ishitani, Haruro,Ueno, Masaharu,Kobayashi, Shū
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p. 211 - 215
(2017/04/21)
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- Exhaustive Chemoselective Reduction of Nitriles by Catalytic Hydrosilylation Involving Cooperative Si-H Bond Activation
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A chemoselective method for the catalytic hydrosilylation of nitriles to either the imine or amine oxidation level is reported. The chemoselectivity is controlled by the hydrosilane used. The usefulness of the nitrile-to-amine reduction is demonstrated for a diverse set of aromatic and aliphatic nitriles, and the amines are easily isolated after hydrolysis as their hydrochloride salts. This exhaustive nitrile reduction proceeds at room temperature.
- Wübbolt, Simon,Oestreich, Martin
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supporting information
p. 2411 - 2414
(2017/10/03)
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- Cobalt-Catalyzed and Lewis Acid-Assisted Nitrile Hydrogenation to Primary Amines: A Combined Effort
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The selective hydrogenation of nitriles to primary amines using a bench-stable cobalt precatalyst under 4 atm of H2 is reported herein. The catalyst precursor was reduced in situ using NaHBEt3, and the resulting Lewis acid formed, BEt3, was found to be integral to the observed catalysis. Mechanistic insights gleaned from para-hydrogen induced polarization (PHIP) transfer NMR studies revealed that the pairwise hydrogenation of nitriles proceeded through a Co(I/III) redox process.
- Tokmic, Kenan,Jackson, Bailey J.,Salazar, Andrea,Woods, Toby J.,Fout, Alison R.
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supporting information
p. 13554 - 13561
(2017/10/05)
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- ESTRA-1,3,5(10),16-TETRAENE-3-CARBOXAMIDES FOR INHIBITION OF 17Β-HYDROXYSTEROID DEHYDROGENASE (AKR1 C3)
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The invention relates to AKR1C3 inhibitors of formula (I) and to processes for preparation thereof, to the use thereof for treatment and/or prophylaxis of diseases and to the use thereof for production of medicaments for treatment and/or prophylaxis of diseases, especially of bleeding disorders and endometriosis.
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- Rapid Conventional and Microwave-Assisted Decarboxylation of L-Histidine and Other Amino Acids via Organocatalysis with R-Carvone under Superheated Conditions
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This article reports a new methodology taking advantage of superheated chemistry via either microwave or conventional heating for the facile decarboxylation of alpha amino acids using the recoverable organocatalyst, R-carvone. The decarboxylation of amino acids is an important synthetic route to biologically active amines, and traditional methods of amino acid decarboxylation are time consuming (taking up to several days in the case of L-histidine), are narrow in scope, and make use of toxic catalysts. Decarboxylations of amino acids including L-histidine occur in just minutes while replacing toxic catalysts with green catalyst, spearmint oil. Yields are comparable to or exceed previous methods and purification of product ammonium chloride salts is aided by an isomerization reaction of residual catalyst to phenolic carvacrol. The method has been shown to be effective for the decarboxylations of a range of natural, synthetic, and protected amino acids.
- Jackson, Douglas M.,Ashley, Robert L.,Brownfield, Callan B.,Morrison, Daniel R.,Morrison, Richard W.
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p. 2691 - 2700
(2015/12/18)
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- METHOD FOR DECARBOXYLATION OF AMINO ACIDS VIA IMINE FORMATION
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The present application provides methods for decarboxylation of amino acids via imine formation with a catalyst under superheated conditions in either a microwave or oil bath.
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Page/Page column 0045; 0047; 0066; 0067
(2014/09/30)
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- A convenient method for the preparation of primary amines using tritylamine
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A simple method for the preparation of primary amines by treating N-tritylamines with trifluoroacetic acid has been established. The N-tritylamines were prepared by the reaction of alkyl halides or alkyl p-toluenesulfonates with tritylamine, or by the reaction of alkyl bromides with lithium tritylamide.
- Theodorou, Vassiliki,Ragoussis, Valentine,Strongilos, Alexandros,Zelepos, Evangelos,Eleftheriou, Argyro,Dimitriou, Maria
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p. 1357 - 1360
(2007/10/03)
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- Phenoxypropanol connected with phenylpiperazine and phenoxyalkylamine terminal in its side chain
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The invention disclosed some 1,4-dihydropiridine derivative chemically have pharmacologically with adrenoceptor blocking and calcium channel blocker is now emerging. The compound of 1,4-dihydropiridine derivative wherein has the formula I, wherein R selected from four group as follow whetherin R present R1 selected from halogen(X), hydrogen(H), saturated C1-C6 alkyl chain, saturated C1-C6 alkyoxyl chain, R2 selected from R3 selected from halogen(X), hydrogen(H), saturated C1-C6 alkyl chain, saturated C1-C6 alkyoxyl chain, and O—(C1-C3)—CF3.
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- Zinc/hydrazine: A low cost-facile system for the reduction of nitro compounds
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The nitro group in aliphatic and aromatic nitro compounds also containing reducible substituents such as ethene, nitrile, carboxylic acid, phenol, halogen, ester etc., are selectively and rapidly reduced at room temperature to corresponding amines in good yields by employing 99-100% hydrazine hydrate, in the presence of commercial zinc dust. It was observed that, this system is equally compatible with existing methods, which employ expensive catalysts like palladium, platinum, ruthenium etc.
- Gowda, Shankare,Gowda, D. Channe
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p. 180 - 183
(2007/10/03)
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- Pyrazolopyrimidinone CGMP PDE5 inhibitors for the treatment of sexual dysfunction
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There is provided compounds of formula IA and of formula IB, wherein R1, R2, R3, R4and A have meanings given in the description, which are useful in the curative and prophylactic treatment of medical conditions for which inhibition of a cyclic guanosine 3′,5′-monophosphate phosphodiesterase (e.g. cGMP PDE5) is desired.
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- Nickel-catalyzed formic acid reductions. A selective method for the reduction of nitro compounds
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Aliphatic and aromatic nitro compounds were selectively reduced to their corresponding amino derivatives in good yields using formic acid and raney nickel. This system is found to be compatible with several sensitive functionalities such as halogens, -OH, -OCH3, -CHO, -COCH3-COC6H5, -COOH, -COOC2H5, -CONH2, -CN, -CH=CH-COOH, -NHCOCH3. The reduction can be carrid out not only with HCOOH but also with HCOONH4.
- Channe Gowda,Prakasha Gowda,Ramesha Baba,Gowda, Shankare
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p. 2889 - 2895
(2007/10/03)
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- Thiazolidinone compounds and composition for angina pectoris comprising the compounds as an active ingredient
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A thiazolidinone compound represented by general formula (I) or a pharmacoligically acceptable salt thereof, STR1 wherein W represents sulfur or oxygen and X represents --N(R1)--, or alternatively X represents sulfur or oxygen and W represents --N(R1)--, and R1 represents hydrogen, alkyl or substituted alkyl; R2 and R3 are the same or different from each other, and each represents hydrogen, alkyl, substituted alkyl, aryl, or 5- or 6-membered heteroaryl; R4 represents hydrogen, alkyl or substituted C1 -C4 alkyl; R5 represents substituted cycloalkyl which may contain nitrogen, provided the substituents include --B--ONO2 (wherein B represents a single bond or alkylene) as the indispensable member and alkyl groups as optional members; and A represents a single bond or alkylene, has an excellent anti-anginal effect and thus is useful as an angina pectoris remedy or preventive.
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- Aminoalkylmaleimides and hapten and antigen derivatives derived therefrom as well as conjugates with peptides or proteins
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The invention concerns new aminoalkylmaleimides of the general formula I STR1 in which R1 and R2 are the same or different and represent hydrogen or a C1 -C4 alkyl group and A represents a straight-chain or branched, saturated or unsaturated alkylene group with 2 to 6 carbon atoms which is interrupted, if desired, by an oxygen or sulphur atom or a carbonyl group, as well as their corresponding acid addition salts. The present invention also concerns amidoalkylmaleimide derivatives formed from compounds of the general formula I and immunological binding partners. In addition, the invention concerns immunological conjugates which can be produced by reaction of the amidoalkylmaleimide derivatives with peptides or proteins. The subject matter of the present invention are also the corresponding processes of production of the compounds according to the present invention as well as the use of these conjugates in diagnostic methods of determination, in particular in immunoassays.
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- METHOD OF TREATING DISORDERS OF THE DOPAMINERGIC SYSTEMS USING 2,5-DIAMINOTETRALINES
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The invention relates to novel 2,5-diaminotetralines of the formula: STR1 wherein R1, R2, R3 and R4 are defined herein, processes for preparing them and their use in pharmaceutical compositions. The novel 2, 5-diaminotetralines are useful in treating diseases caused by disorders of the dopaminergic systems.
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- Conversion of Aliphatic Amides into Amines with benzene. Scope of the Reaction
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The reagent benzene, PIFA, brings about the facile oxidative rearrangement of aliphatic amides to amines in mildly acidic (pH 1-3) mixed aqueous-organic solvents.Aromatic amines are further oxidized by the reagent and therefore cannot be prepared by this method.The rearrangement, which is in effect an "Hofmann rearrangement", occurs with complete retention of configuration in the migrating group, and the rate of the reaction follows approximately the migratory aptitudes of the migrating groups determined for other similar reactions.Isocyanates are intermediates in the rearrangement but are rapidly hydrolyzed to the product amines under the mildly acidic conditions.The acidic conditions protect the product amines from reacting with the isocyanate intermediates and forming ureas.The reaction is accelerated by addition of pyridine to a pH of approximately 3.The scope of the reaction is discussed.
- Loudon, G. Marc,Radhakrishna, A. S.,Almond, Merrick R.,Blodgett, James K.,Boutin, Raymond H.
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p. 4272 - 4276
(2007/10/02)
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- A Simple Synthesis pf Primary Amines via their N,N-Bis(trimethylsilyl) Derivatives
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Primary halogen compounds 1 or the corresponding tosylates react with sodium bis(trimethylsilyl)amide (2) in hexamethyldisilazane to form N,N-bis(trimethylsilyl)amines 3, which are converted into the amine hydrochlorides 5 by treatment with aqueous HCl.
- Bestmann, Hans Juergen,Woelfel, Gerhard
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p. 1250 - 1254
(2007/10/02)
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- Thiadizines
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Novel heterocyclic compounds of the formula: STR1 wherein either X is --CR1 R2 -- and Y is oxygen, sulphur or --NR3, wherein R1, R2 and R3, which may be the same or different, each is hydrogen or alkyl of up to 4 carbon atoms; or X is oxygen, sulphur or --NH-- and Y is --CH2 --; wherein R4 and R5, which may be the same or different, each is hydrogen, cyano, nitro, amino or hydroxy, or alkylthio of up to 4 carbon atoms, or has various other meanings defined in claim 1, provided that R4 and R5 are not both hydrogen; or wherein R4 and R5 are joined together such that with the benzene ring A they form a benzheterocyclic ring as defined in claim 1; and therein the benzene ring A may optionally bear one or more further substituents; or a salt thereof where appropriate. These compounds possess cardiotonic properties, and some of them possess peripheral vasodilator properties, and they are useful for the treatment of acute or chronic heart failure. Representative of the compounds is N,N-dimethyl-p-(5,6-dihydro-5-oxo-4H-1,3,4-thiadiazin-2-yl)benzamide. Also disclosed are processes for the manufacture of the compounds and pharmaceutical compositions containing them.
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- Lithiation of α-Nitrosaminoalkyl Ethers. Synthetic Equivalents of α-Primary Amino Carbanions
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Successful experiments directed toward the C-1 alkylation and hydroxyalkylation of primary amines are reported.Primary amines are converted into their N-nitroso-N-(1-methoxyethyl) derivatives, which are subsequently lithiated and condensed with various electrophiles, denitrosated, and hydrolyzed to produce the desired compounds in good to excellent yields.
- Saavedra, Joseph E.
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p. 2388 - 2392
(2007/10/02)
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- Caustic-free process for the production of monochloro-diamino-s-triazines
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A new and improved process is provided for preparing monochloro-diamino-s-triazines which are useful as herbicides. The process comprises reacting in a first stage cyanuric chloride and a selected monoalkylamine hydrochloride at elevated temperature to give a dichloro-monoalkylamino-s-triazine and reacting in a second stage this dichloro-monoalkylamino-s-triazine with an excess of a different monoalkylamine which may be introduced as a pure liquid, as gas or as a solution in water. The third stage of the process consists of an exchange whereby the monoalkylamine hydrochloride of the first stage and the free monoalkylamine of the second stage are generated. The process gives consistent yields in excess of 97% of monochloro-diamino-s-triazines. Because the process is caustic-free and due to the feasibility of recycling the excess of monoalkylamines employed, no serious effluent problems arise.
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- Novel monophosphates
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Novel 5-lower alkyl-2'-desoxyuridine-5'-monophosphates of the formula STR1 wherein R is lower alkyl of 2 to 6 carbon atoms having antiviral activity.
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- Carboxyl terminated polydienes
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Carboxyl terminated polymers prepared by reacting a cyclic anhydride with a liquid polymeric hydroxyl terminated polymer selected from polyethers, polydienes, and copolymers of the dienes with styrene or acrylonitrile in the presence of a catalyst selected from quaternary ammonium salts and from halogen acid salts of amines. The carboxyl terminated polymers can be used as flexibilizers in epoxy resins.
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