Phenylthiourea, structure

I-Cyano-3-phenylurea, first obtained by the alkaline hydrolysis of 5-anilino-3- -toluyl-l,2,4-oxadiazole, has been prepared by tlic condensation of phenyl isocyanate and the sodium salt of cyanamide. However, in these publications an incorrect structural assignment for the product was made. 1-Cyano-3-phenyl-urea is obtained also, together with other products, by warming gently l-cyano-3-phenylthiourea with caustic soda in the presence of ethylene chlorohydrin, or by gradually adding caustic )otash to a boiling solution of 1-phenyldithiobiuret and ethylene clilorohydrin in ethanol. ... 

To a solution of triphenyl phosphite (6.2 g, 0.02 mol) and thiomethoxy-acetaldehyde (2.25 g, 0.025 mol) in glacial acetic acid (18 ml), powdered N-phenylthiourea was added in a single portion. The reaction mixture was stirred at room temperature for 30 min and then for 30 min at 80°C. After the mixture was cooled to room temperature, water (5 ml) was added and the solution was maintained at room temperature for 10 h. The precipitate was removed by suction filtration, washed with 1 1 acetic acidtwater (2 x 10 ml), dried over potassium hydroxide in an evacuated dessicator, and recrystallized from chloroform/ methanol. In this manner there was isolated pure 0,0-diphe-nyl 2-methylthio-l-(iV-phenylthioureido)ethylphosphonate (8.61 g, 94%) of mp 136 to 138°C, which exhibited spectra and analytical data in accord with the proposed structure. 

Sweetness Production by the Combination of Bitter and Sweet Tastes. Sensory tests using typically bitter compounds such as brucine, strychnine, phenylfiiiourea, caffeine and bitter peptides were performed. Sensory tests using typically bitter compounds such as brucine, strychnine, phenylthiourea, caffeine and bitter peptides were performed. Sensory taste impression were also measured for combinations of acetic acid (sour) and typical bitter compounds (5). The data from these studies indicated that the tastes of ese bitter/sour mixtures changed to a sweet taste regardless of their chemical structure of the bitter component (Table II). 

Many important organosulfur compounds also contain nitrogen. One such compound is thiourea, the sulfur analog of urea. Its structural formula is shown in Figure 1.19. Thiourea and phenylthiourea have been used as rodenticides. Commonly called ANTU, 1-naphthylthiourea is an excellent rodenticide that is virtually tasteless and has a very high rodent human toxicity ratio. 

Fig. 8 Model for the response of polynucleotide-sensitive copolymers of NIPAM and derivatives of phenylboronic acid and phenylthiourea on silicon surfaces. Interaction with the nucleotide is supposed to result in unwinding of the polymer structure, causing decrease in contact angle by exposure of hydrophilic moieties. Reprinted, with permission, from [83]. Copyright (2009) American Chemical Society...

In 1998, Krebs and co-authors reported the crystal structures of the catechol oxidase isolated from sweet potatoes (Ipomoea batatas) in three catalytic states the native met (CunCun) state (Figure 5.2a), the reduced deoxy (Cu Cu1) form, and the complex with the inhibitor phenylthiourea (Figure 5.2b) [19]. Typically for the type 3 active site, each copper ion is coordinated by three histidine residues from the protein backbone. In the native met state, the two copper ions are 2.9 A apart and, in addition to six histidine residues, a bridging solvent molecule, most likely a hydroxide anion, has been refined in close proximity to the two metal centers... 

Figure 5.2 (a) Coordination sphere of the dinudear copper(ll) center in the met state, (b) Crystal structure of the inhibitor complex of catechol oxidase with phenylthiourea. Redrawn after Krebs and co-workers [60]. 

The crystal structure of the dithioacetylacetone (sacsacH) complex of cobalt(n), Co(sacsac)2, shows it to be monomeric square planar,164 in marked contrast to the acacH analogue. Pyridine 2-thiol (LH), which can exist as the thione tautomer (31) forms Co(LH)2X2 (X = Cl, Br, or I) complexes these contain the ligand bonded through the sulphur, as evidenced by the presence of a v(N—H) vibration in the i.r. spectra.165 Morpholine 4-thiocarbonic acid (32) also appears to be S-bonded in the CoL2X2 complexes (X = Cl, Br, or I), since the v(C=S) frequency is lowered upon co-ordination.166 The electronic spectra of the CoL2C12 complexes (L = thiourea, A-phenylthiourea, and TViV -diphenylthiourea) have been recorded.167... 

Figure 3 Active site structure of the inhibitor (phenylthiourea, PTU) bound catechol oxidase from sweet...

S. antibioticus tyrosinase 37), spectroscopic studies on biomimetic catecho-late-dicopper(II) complexes 38), and by the structure of the catechol oxidase complex with phenylthiourea 25). Like hemocyanin and catechol oxidase, also tyrosinase exhibits a weak catalase activity 39,40). 

In this extensive study of thiourea synthesis by coupling isothiocyanates with amines under mechanochemical conditions of neat and LAG, a total of 49 different thiourea derivatives were prepared. Since the supramolecular chemistry of simple synunetrical and nonsymmetrical diarylthiouieas had not previously been studied in detail, the information from the PXRD patterns of the milling products in this work also allowed for a systematic analysis of structural features of diarylthio-ureas. The three main self-assembly motifs were identified. A characteristic supramolecular synthon based on bifurcated N—H - S hydrogen bonds was found in most cases, whereby the individual thiourea molecules were assembled into chains aligned in a head-to-head (parallel molecular dipoles) or head-to-tail (antiparallel molecular dipoles) manner. In the case of slerically hindered thioureas, such as A -(2,6-dimethylphenyl)-A -phenylthiourea, the third motif arising from discrete cen-trosymmetric dimers based on rI(S) supramolecular synthon was found. A detailed look at the measured PXRD patterns for aU diarylthioureas revealed that solid-state structures of these compounds could be classified into two structural families, denoted as family I and family II (Fig. 1.11). 

I may mention some examples of chemical characters. One of our chemical senses is the sense of taste—the taste of a substance depends upon the structure of its molecules. There are two kinds of people with respect to ability to taste a certain substance, phenylthiourea. This substance seems to some people to be very bitter, whereas to others it is quite tasteless. The inheritance of this character is determined by a single gene, transmitted by the pure Mendelian mechanism. 

A new sesquiterpene skeleton has been identified in an isocyanide isolated from Phillidia varicosa, and the name pupukeanane (after the locality where the molluscs were obtained) has been suggested for this carbon framework. X-Ray analysis of the crystalline phenylthiourea derived from 9-isocyanopupukeanane (4) established the structure. The structure of stemarin tosylate reveals a new diterpene skeleton (5). Crystal structures reported for various other bridged carbocyclics are reported in other, more appropriate, chapters of this volume. 

All attempts to chlorosulfonate phenylthiourea 387 to the p-sulfonyl chloride failed and even with a large excess of chlorosulfonic acid (six equivalents) under drastic conditions (120-130 °C, 6 hours), the only product was the iminosulfonic acid 388. The latter probably arises from sulfonation of the favoured thiol tautomer and the proposed zwitterionic structure of 388 would account for its inertness towards phosphorus pentachloride. ... 

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