One procedure for the introduction of sulfur atom into the pyrrole ring is based on the reaction of pyrroles with thiocyanogen, which leads to 2-thiocyanatopyrroles [1]; the latter can be converted into 2-alkylsulfanylpyrroles by reaction with alkyl halides in the presence of bases [1]. The thiocyanation of pyrrole with thiocyanogen occurs at the 2-position of the pyrrole ring, whereas indole reacts with thiocyanogen to give 3-thiocyanatoindole [2]. 4,5,6,7-Tetrahydroindole (I) is an important heterocyclic compound which is used to prepare many difficultly accessible substances [3], including indole derivatives. Some difficultly accessible indole derivatives functionalized at the 2-position were synthesized by reaction of I with electrophiles and subsequent dehydrogenation [4]. The reaction of thiocyanogen with tetrahydroindole (I) was not reported. The site of electrophilic substitution in molecule I cannot be always predicted a priori. For example, formylation of 1-vinyl-4,5,6,7-tetrahydroindole involves the 2-position [5], whereas the reaction of I with 6-chloropyrimidine-4-carbonyl chloride resulted in electrophilic substitution at C [6]. We were the first to react tetrahydroindole (I) with thiocyanogen with formation of previously unknown 2-thiocyanato-4,5,6,7-tetrahydroindole (II) in 80% yield. Thiocyanogen was prepared in situ by addition of bromine to a suspension of potassium thiocyanate in methanol at –65 to –78°C. A solution of I in methanol was cooled to –78oC and added in one portion to a solution of thiocyanogen, and the mixture was stirred for 3 h at –65 to –78°C and allowed to warm up to room temperature. The structure of II was proved by H and C NMR spectroscopy with the aid of HMBC (C–H) and HSQC (C–H) two-dimensional correlation techniques. Thus, the thiocyanation of tetrahydroindole (I) with thiocyanogen occurs at the 2-position with formation of 2-thiocyanato-4,5,6,7-tetrahydroindole (II) which is promising as intermediate product for the synthesis of sulfanyl derivatives of tetrahydroindole. Compound I was prepared by the Trofimov reaction from cyclohexanone oxime and acetylene [3]. 2-Thiocyanato-4,5,6,7-tetrahydro-1H-indole (II). Dark yellow oily substance. H NMR spectrum (CDCl3), δ, ppm: 1.67–1.74 m (2H, 5-H), 1.74–1.81 m (2H, 6-H), 2.44 t (2H, 4-H, J = 5.5 Hz), 2.54 t (2H, 7-H, J = 5.9 Hz), 6.34 s (1H, 3-H), 8.26 s (NH). C NMR spectrum (CDCl3), δC ppm: 22.56 (C), 22.77 (C), 22.83 (C), 23.29 (C), 99.57 (SCN), 111.23 (C), 119.36 (C), 120.40 (C), 134.41 (C). Found, %: C 60.32; H 5.52; N 15.98; S 18.21. C9H10N2S. Calculated, %: C 60.64; H 5.65; N 15.72; S 17.99. The H and C NMR spectra were recorded on a Bruker DPX-400 spectrometer at 400.13 and 100.61 MHz, respectively, using CDCl3 as solvent and hexamethyldisiloxane as internal reference. ISSN 1070-4280, Russian Journal of Organic Chemistry, 2013, Vol. 49, No. 4, pp. 619–620. © Pleiades Publishing, Ltd., 2013. Original Russian Text © V.A. Potapov, K.A. Volkova, D.A. Malinovich, A.V. Ivanov, A.I. Albanov, S.V. Amosova, 2013, published in Zhurnal Organicheskoi Khimii, 2013, Vol. 49, No. 4, pp. 634–635.