Phenylacetyl isothiocyanate (1) was reacted with benzoyl hydrazine (2a) in acetonitrile to give thiosemicarbazide derivative 3 which was cyclized by polyphosphoric acid to give 1,2,4-triazoline-5-thione derivative 4. Treatment of 1 with thiosemicarbazide (2b) yielded another 1,2,4-triazoline-5-thione derivative 5. Similar treatment of 1 with phenyl hydrazine (2c) in acetonitrile gave a differently substituted 1,2,4-triazoline-5-thione derivative 6 in one pot-reaction. On the other hand, when the reaction was carried out in acetone, a mixture of 6 and thiadiazolidine derivative 7 was obtained. However, reaction of 1 with hydrazine hydrate (2d) gave hydrazine derivative 8. Reaction of isothiocyanate 1 with anthranilic acid (9) gave benzo [d] [1,3,6]oxazin-1-one derivative 10. Treatment of 1 with 2-aminothiophenol (11a), 2-aminophenol (11b) or o-phenylenediamine (11c) produced benzothiazole derivative 12a, benzoxazole derivative 12b and benzimidazole derivative 12c, respectively. The structures of all the products were confirmed by micro-analytical and spectral data.

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A series of 5,5‐diarylhydantoin (Dilantin) 3, 4, and 7, imidazole 1, 2, 5, 6, 8, and 9, thiazole 10–12, triazinthione 13, 15, 16, and 17, and thiadiazine 14 derivatives, containing diverse hydrophobic groups, were green synthesized through one‐pot stepwise reaction of aromatic aldehydes, vitamin B1, and nitrogen nucleophiles, for example, urea, thiourea, and thiosemicarbazide using grinding technique as well as conventional thermal methods. Such synthesized compounds have potent insecticidal activities; for example, compounds 4, 6, and 17 exhibited the highest insecticidal activity against both Plutella xylostella and Helicoverpa armigera with minimum inhibitory concentration values at 500 μg/mL and LD50 activities at 50 μg/mL. The density functional theory was then applied to explore the structural and electronic characteristics of these compounds. All the synthesized compounds have been characterized based on their elemental analyses and spectral data.

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The reaction of lauroyl isothiocyanate and 2-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carbonitrile was used to synthesize the title compound 2. Compound 2 could serve as the main building block in the synthesis of many target heterocyclic systems. Various fused pyrimidines were synthesized in the reactions of compound 2 with sodium ethoxide, hydrazine hydrate, phenyl hydrazine, ethyl carbazate, thiourea, and/ or 2-aminothiophenol. The structures of the synthesized compounds were confirmed by microanalytical and spectral data.Key words lauroyl isothiocyanate; pyrimidine derivative; fused system; 2-amino-4,5,6,7-tetrahydrobenzo[b]-thiophene-3-carbonitrile Pyrimidine and fused heterocyclic pyrimidine derivatives have received significant attention over the past few years owing to their therapeutic and pharmacological properties.

Phthalimidoacetyl isothiocyanate underwent addition-cyclization reactions with some nitrogen and carbon nucleophilic reagents. Simultaneous or subsequent cyclization of the obtained adducts gave target heterocyclic systems such as 1,2,4-triazoles, 1,3-diazines, 1,3-oxazines and thiourea attached to a phthalimido moiety. The antimicrobial activity of the synthesized compounds was tested.Key words phthalimidoacetyl isothiocyanate; 1,2,4-triazol; 1,3-diazine; 1,3-oxazine; thiourea; antimicrobial are well known.In the past few years the authors have been involved in the uses of aroyl isothiocyanates [17][18][19][20] and acyl isothiocyanates [21][22][23][24] in different synthetic strategies of target heterocycles. Studies on the chemistry of aroyl and/or acyl isothiocyanates have established the value of these compounds as starting materials in the synthesis of a wide variety of heterocyclic systems and thiourea derivatives. [17][18][19][20][21][22][23][24][25][26][27] Based on the previous work, we have been synthesized variety of heterocyclic systems bearing phthalimido moiety by using 2-phthalimidobenzoyl isothiocyanate 19) and phthalimidoacyl isothiocyanate.22) In the current study, a further stage reactions of phthalimidoacetyl isothiocyanate was performed. Results and DiscussionTreatment of a solution of phthalimidoacetyl isothiocyanate 1 in a dry acetonitrile with 2-cyanoacetohydrazide at room temperature gave thiosemicarbazide derivative 2 in a good yield. On the other hand, the reaction of a mixture of isothiocyanate 1 and 2-cyanoacetohydrazide in acetonitrile under refluxing conditions produced 1,2,4-triazole derivative 3 in one pot-reaction. However, boiling a solution of the adduct 2 in acetonitrile also gave the 1,2,4-triazole derivative 3. Refluxing of compound 3 in ethanolic-hydrochloric acid mixture afforded ester derivative 4. On the other hand, when a solution of 3 in ethanol was boiled with a catalytic amount of sodium hydroxide, followed by acidification with dilute HCl furnished a carboxylic acid derivative 6 as illustrated in Chart 1.The structures of the synthesized compounds 2-4 and 6 were elucidated from their microanalytical and spectral data. Thus, their IR spectra displayed bands corresponding to NH, CO and C=S, as well as stretching band of CN group for compounds 2 and 3. The 1 H-NMR spectra of the synthesized compounds are in accord with their proposed structures as they showed signals for aromatic protons and aliphatic protons in addition to NH protons in the downfield region exchangeable with D 2 O. The appearance of an exchangeable broad singlet signal for compound 4, at δ: 7.16 ppm corresponds to SH proton suggests its existence entirely as aromatic triazole structure. The relatively high δ value of SH proton suggests chelation shown (Chart 1). The 1 H-NMR spectrum of compound 6 showed the absence of a signal corresponding to CH 2 protons in the up field region, instead it revealed two olefinic signals at δ: 5.88 and 5.94 ppm integrated to one proton. These observations suggest that...

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