Phenothiazinimides: Atom-Efficient Electrophilic Amination Reagents

Abstract

Phenothiazinimides, a fairly unknown class of imines, were prepared and found to be very reactive as ultrasimple atom-efficient electrophilic amination reagents for phenols and indoles under metal-free conditions.

HBF4- and AgBF4-Catalyzed ortho-Alkylation of Diarylamines and Phenols

“…This is moreover a synthetically interesting regioselectivity outcome in light of the usual preference of phenothiazine for C3-( para -) electrophilic aromatic substitution. 9 This strong preference for the ortho-branched alkylated product is in good agreement with the concerted mechanism of Scheme 1. Even 1,1-and 1,2-disubstituted styrenes were found to be competent hydroarylation substrates, albeit in lower yields ( 3i , 43%; 3j , 38%).…”

“…In some cases, small amounts of bis-alkylated products can be observed (i.e., Table , entry 1); however, the first alkylation step seems to consistently occur in the ortho position to the X–H functional group (Scheme ). This is moreover a synthetically interesting regioselectivity outcome in light of the usual preference of phenothiazine for C3-( para -) electrophilic aromatic substitution . This strong preference for the ortho-branched alkylated product is in good agreement with the concerted mechanism of Scheme .…”

Synthesis and Spectroscopic Characterization of Selected Phenothiazines and Phenazines Rationalized Based on DFT Calculation

“…The N -benzoylated, N -alkylated, or N -arylated phenothiazines and related compounds are stable molecules [ 23 , 24 , 25 , 26 , 27 ]. Some of their representatives are highly potent inhibitors of cancer cell growth and tubulin polymerization [ 26 ].…”

“…3,7-Dinitro-10 H -phenothiazine 5-oxide ( 3 ) [ 24 ] 10.5 g (34.4 mmol, 68.5 %) as a yellow powder, mp dec. = 310.0-316.5 °C; 1 H-NMR (DMSO-d 6 ; 500.2 MHz) δ = 7.61 (d, 3 J H,H = 9.1 Hz, 2H, aromatic), 8.48 (dd, 3 J H,H = 9.1 Hz, 4 J H,H = 2.6 Hz, 2H, aromatic), 8.96 (d, 4 J H,H = 2.6 Hz, 1H, aromatic), 12.32 (s, 1H, NH); 1 H-NMR (DMSO-d 6 /KOD; 500.2 MHz) δ = 7.56 (d, 3 J H,H = 9.1 Hz, 2H, aromatic), 8.42 (dd, 3 J H,H = 9.1 Hz, 4 J H,H = 2.7 Hz, 2H, aromatic), 8.89 (d, 4 J H,H = 2.6 Hz, 1H, aromatic); 13 C{ 1 H}-NMR (DMSO-d 6 ; 100.6 MHz) δ = 118.8, 121.5, 128.1, 128.2, 139.9, 141.7; 13 C{ 1 H}-NMR(DMSO-d 6 /KOD; 100.6 MHz) δ = 120.2, 121.2, 127.7, 128.4, 140.9, 141.9; CCDC (The Cambridge Crystallographic Data Centre) 2177509.…”

Leucomethylene blue probe detects a broad spectrum of reactive oxygen and nitrogen species

“…Towards 2, we have first prepared a 2,8-diaminoacyl phenothiazine derivative (PTZ-NHAc, 3) from 3,7-dinitro-10 H -phenothiazine-5-oxide (see ESI † ) as reported previously. 39 Then, for introducing the BHP unit at 3, a convenient metal-free dehydrogenative amination method was applied based on a recently published route ( Scheme 1B ). 40 An advantage of this route is also the high stability of 3 and 4 towards oxygen.…”