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Thioureas
In organic chemistry, thioureas are members of a family of organosulfur compounds with the formula and structure . The parent member of this class of compounds is thiourea (). The thiourea functional group has a planar core. Structure and bonding Thioureas have planar core. The bond distance is near 1.71 Å, which is 0.1 Å longer than in normal ketones (). The C–N bond distances are short. Thioureas occurs in two tautomeric forms. For the parent thiourea, the thione form predominates in aqueous solutions. The thiol form, known as an isothiourea, can be encountered in substituted compounds such as isothiouronium salts. : Synthesis ''N'',''N''′-unsubstituted thioureas can be prepared by treating the corresponding cyanamide with hydrogen sulfide or similar sulfide sources. Organic ammonium salts react with potassium thiocyanate as the source of the thiocarbonyl (). Alternatively, ''N'',''N''′-disubstituted thioureas can be prepared by coupling two ami ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thiourea Functional Group
Thiourea () is an organosulfur compound with the formula and the structure . It is structurally similar to urea (), except that the oxygen atom is replaced by a sulfur atom (as implied by the ''thio-'' prefix); however, the properties of urea and thiourea differ significantly. Thiourea is a reagent in organic synthesis. "Thioureas" refer to a broad class of compounds with the general structure . Thioureas are related to thioamides, e.g. , where R is methyl, ethyl, etc. Structure and bonding Thiourea is a planar molecule. The C=S bond distance is 1.71 Å. The C-N distances average 1.33 Å. The weakening of the C-S bond by C-N pi-bonding is indicated by the short C=S bond in thiobenzophenone, which is 1.63 Å. Thiourea occurs in two tautomeric forms, of which the thione form predominates in aqueous solutions. The equilibrium constant has been calculated as ''K''eq is . The thiol form, which is also known as an isothiourea, can be encountered in substituted compounds such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thiourea Tautomers
Thiourea () is an organosulfur compound with the formula and the structure . It is structurally similar to urea (), except that the oxygen atom is replaced by a sulfur atom (as implied by the ''thio-'' prefix); however, the properties of urea and thiourea differ significantly. Thiourea is a reagent in organic synthesis. "Thioureas" refer to a broad class of compounds with the general structure . Thioureas are related to thioamides, e.g. , where R is methyl, ethyl, etc. Structure and bonding Thiourea is a planar molecule. The C=S bond distance is 1.71 Å. The C-N distances average 1.33 Å. The weakening of the C-S bond by C-N pi-bonding is indicated by the short C=S bond in thiobenzophenone, which is 1.63 Å. Thiourea occurs in two tautomeric forms, of which the thione form predominates in aqueous solutions. The equilibrium constant has been calculated as ''K''eq is . The thiol form, which is also known as an isothiourea, can be encountered in substituted compounds such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thiourea
Thiourea () is an organosulfur compound with the formula and the structure . It is structurally similar to urea (), except that the oxygen atom is replaced by a sulfur atom (as implied by the ''thio-'' prefix); however, the properties of urea and thiourea differ significantly. Thiourea is a reagent in organic synthesis. " Thioureas" refer to a broad class of compounds with the general structure . Thioureas are related to thioamides, e.g. , where R is methyl, ethyl, etc. Structure and bonding Thiourea is a planar molecule. The C=S bond distance is 1.71 Å. The C-N distances average 1.33 Å. The weakening of the C-S bond by C-N pi-bonding is indicated by the short C=S bond in thiobenzophenone, which is 1.63 Å. Thiourea occurs in two tautomeric forms, of which the thione form predominates in aqueous solutions. The equilibrium constant has been calculated as ''K''eq is . The thiol form, which is also known as an isothiourea, can be encountered in substituted compounds such a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethylene Thiourea
Ethylene thiourea (ETU) is an organosulfur compound with the formula . It is an example of an ''N'',''N''-disubstituted thiourea. It is a white solid. It is synthesized by treating ethylenediamine with carbon disulfide. Ethylene thioureas are an excellent accelerant of vulcanization of neoprene rubbers. In commercial use is the N,N'-diphenylethylenethiourea. Due to reproductive toxicity, carcinogenicity, and mutagenicity, alternatives are being sought to the ethylenethioureas. One candidate replacement is N-methyl-2-thiazolidinethione. Ethylene thiourea can be used as a biomarker of exposure to ethylenebis dithiocarbamates (EBDTCs), which are frequently employed as fungicides in agriculture, mainly on fruits, vegetables and ornamental plants. EPA classification EPA The Environmental Protection Agency (EPA) is an independent executive agency of the United States federal government tasked with environmental protection matters. President Richard Nixon proposed the estab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethylenethiourea
Ethylene thiourea (ETU) is an organosulfur compound with the formula . It is an example of an ''N'',''N''-disubstituted thiourea. It is a white solid. It is synthesized by treating ethylenediamine with carbon disulfide. Ethylene thioureas are an excellent accelerant of vulcanization of neoprene rubbers. In commercial use is the N,N'-diphenylethylenethiourea. Due to reproductive toxicity, carcinogenicity, and mutagenicity, alternatives are being sought to the ethylenethioureas. One candidate replacement is N-methyl-2-thiazolidinethione. Ethylene thiourea can be used as a biomarker of exposure to ethylenebis dithiocarbamates (EBDTCs), which are frequently employed as fungicides in agriculture, mainly on fruits, vegetables and ornamental plants. EPA classification EPA The Environmental Protection Agency (EPA) is an independent executive agency of the United States federal government tasked with environmental protection matters. President Richard Nixon proposed the estab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isothiouronium
In organic chemistry, isothiouronium is a functional group with the formula SC(NH2)2sup>+ (R = alkyl, aryl) and is the acid salt of isothiourea. The H centres can also be replaced by alkyl and aryl. Structurally, these cations resemble guanidinium cations. The CN2S core is planar and the C–N bonds are short. Synthesis Salts comprising these cations are typically prepared by alkylation of thiourea: :SC(NH2)2 + RX → SC(NH2)2sup>+X− Reactions Hydrolysis of isothiouronium salts gives thiols. : SC(NH2)2sup>+X− + NaOH → RSH + OC(NH2)2 + NaX Isothiouronium salts in which the sulfur has been alkylated, such as ''S''-methylisothiourea hemisulfate (CAS number: 867-44-7), will convert amines into guanidinium groups. This approach is sometimes called the Rathke synthesis after Bernhard Rathke who first reported it in 1881. : RNH2 + eSC(NH2)2sup>+X− → RNC(NH2)2]+X− + MeSH Chelating resins Chelating resins are a class of ion-exchange resins. They are almost always ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thiophosgene
Thiophosgene is a red liquid with the formula . It is a molecule with trigonal planar geometry. There are two reactive C–Cl bonds that allow it to be used in diverse organic syntheses. Preparation is prepared in a two-step process from carbon disulfide. In the first step, carbon disulfide is chlorinated to give trichloromethanesulfenyl chloride ( perchloromethyl mercaptan), : : The chlorination must be controlled as excess chlorine converts trichloromethanesulfenyl chloride into carbon tetrachloride. Steam distillation separates the trichloromethanesulfenyl chloride, a rare sulfenyl chloride, and hydrolyzes the sulfur monochloride. Reduction of trichloromethanesulfenyl chloride produces thiophosgene: : Tin and dihydroanthracene have been used for the reducing agents. Reactions is mainly used to prepare compounds with the connectivity where X = OR, NHR. Such reactions proceed via intermediate such as CSClX. Under certain conditions, one can convert primary amines into isothi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thiocyanates
Thiocyanate (also known as rhodanide) is the anion . It is the conjugate base of thiocyanic acid. Common derivatives include the colourless salts potassium thiocyanate and sodium thiocyanate. Mercury(II) thiocyanate was formerly used in pyrotechnics. Thiocyanate is analogous to the cyanate ion, , wherein oxygen is replaced by sulfur. is one of the pseudohalides, due to the similarity of its reactions to that of halide ions. Thiocyanate used to be known as rhodanide (from a Greek word for rose) because of the red colour of its complexes with iron. Thiocyanate is produced by the reaction of elemental sulfur or thiosulfate with cyanide: : 8 CN- + S8 -> 8 SCN- : CN- + S2O3^2- -> SCN- + SO3^2- The second reaction is catalyzed by thiosulfate sulfurtransferase, a hepatic mitochondrial enzyme, and by other sulfur transferases, which together are responsible for around 80% of cyanide metabolism in the body. Biological chemistry of thiocyanate in medicine Thiocyanate is known to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transamidation
Transamidation is a chemical reaction in which an amide reacts with an amine to generate a new amide: :RC(O)NR'2 + HNR"2 → RC(O)NR"2 + HNR'2 The reaction is typically very slow, but it can be accelerated with Lewis acid and organometallic catalysts. Primary amides (RC(O)NH2) are more amenable to this reaction. Ureas In contrast to the reluctance of amides as substrates, urea is more susceptible to this exchange process. Transamidation is practiced, sometimes even on an industrial scale, to prepare a variety of N-substituted ureas: :(H2N)2CO + R2NH → (R2N)(H2N)CO + NH3 :(R2N)(H2N)CO + R2NH → (R2N)2CO + NH3 Methylurea, precursor to theobromine, is produced from methylamine and urea. Phenylurea is produced similarly but from anilinium chloride:{{cite journal , authors= , title=Arylureas II. Urea Method p-Ethoxyphenylurea , journal=Org. Synth. , year=1951 , volume=31 , page=11 , doi=10.15227/orgsyn.031.0011 :(H2N)2CO + 6H5NH3l → (C6H5(H)N)(H2N) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Chemistry
Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms.Clayden, J.; Greeves, N. and Warren, S. (2012) ''Organic Chemistry''. Oxford University Press. pp. 1–15. . Study of structure determines their structural formula. Study of properties includes physical and chemical properties, and evaluation of chemical reactivity to understand their behavior. The study of organic reactions includes the chemical synthesis of natural products, drugs, and polymers, and study of individual organic molecules in the laboratory and via theoretical ( in silico) study. The range of chemicals studied in organic chemistry includes hydrocarbons (compounds containing only carbon and hydrogen) as well as compounds based on carbon, but also containing other elements, especially oxygen, nitrogen, sulfur, phosphorus (inclu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethylenediamine
Ethylenediamine (abbreviated as en when a ligand) is the organic compound with the formula C2H4(NH2)2. This colorless liquid with an ammonia-like odor is a basic amine. It is a widely used building block in chemical synthesis, with approximately 500,000 tonnes produced in 1998.Karsten Eller, Erhard Henkes, Roland Rossbacher, Hartmut Höke "Amines, Aliphatic" in Ullmann's Encyclopedia of Industrial Chemistry, 2005 Wiley-VCH Verlag, Weinheim. Ethylenediamine is the first member of the so-called polyethylene amines. Synthesis Ethylenediamine is produced industrially by treating 1,2-dichloroethane with ammonia under pressure at 180 °C in an aqueous medium:Hans-Jürgen Arpe, Industrielle Organische Chemie, 6. Auflage (2007), Seite 245, Wiley VCH : In this reaction hydrogen chloride is generated, which forms a salt with the amine. The amine is liberated by addition of sodium hydroxide and can then be recovered by . Diethylenetriamine (DETA) and triethylenetetramine (TETA) ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thiocarbonyl
In organic chemistry, thioketones (; also known as thiones or thiocarbonyls) are organosulfur compounds related to conventional ketones in which the oxygen has been replaced by a sulfur. Instead of a structure of , thioketones have the structure , which is reflected by the prefix "thio-" in the name of the functional group. Unhindered alkylthioketones typically tend to form polymers or rings. Structure and bonding The C=S bond length of thiobenzophenone is 1.63 Å, which is comparable to 1.64 Å, the C=S bond length of thioformaldehyde, measured in the gas phase. Due to steric interactions, the phenyl groups are not coplanar and the dihedral angle SC-CC is 36°. Unhindered dialkylthiones polymerize or oligomerize but thiocamphor is well characterized red solid. Consistent with the double bond rule, most alkyl thioketones are unstable with respect to dimerization.Organosulfur Chemistry I: Topics in Current Chemistry, 1999, Volume 204/1999, 127-181, The energy difference bet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
