Synthetic Reactions in PEG: PEG-Assisted Synthesis of 2-Cyano-6-methoxybenzothiazole, A Key Intermediate For The Synthesis of Firefly Luciferin

2,6-Disubstituted benzothiazoles, analogues of the aromatic core of D-luciferin: synthesis and evaluation of the affinity for Photinus pyralis luciferase

“…The synthesis of 2-cyano-6-methoxybenzothiazole 3e has been fully described, [15][16][17][18] but we started from the commercially available compound. The nitrile 3e can be transformed into the 6-hydroxy analogue 3a carrying out the demethylation by fusion with pyridinium hydrochloride (Py.HCl) at 200 °C.…”

“…11,12 However, due to the instability of the thiazoline moiety of 1a or 1d, chemical manipulations of these compounds were excluded. 13 We next considered to introduce 18 F into benzothiazoles corresponding to the aromatic core of compounds 1a or 1d and 2,6-disubstituted benzothiazoles 2a were selected as starting material for the preparation of compounds 1e. Figure 2.…”

Synthesis of 2-substituted-6-hydroxy and 6-methoxy benzothiazoles from 1,4-benzoquinone

“…This is worth of note, since yields are higher than those obtained following the classical approach (9.9%) 10 and comparable with the most convenient synthesis based on a Sandmeyer approach, using poisonous cyanides (48,6%). 13,14 Finally, our synthetic approach opens the possibility of preparing 2,6-disubstituted benzothiazoles suitable for 18 F labeling such as compounds 2a starting from properly substituted 1,4-benzoquinones. Alternatively, from the ester 8 also new 18 F-labeled amides 2d may become available.…”

“…It should be mentioned that the nitrile 3 is an important intermediate for the synthesis of Dluciferin 9,10 and that the synthesis of this compound has been the target of several publications. [10][11][12][13][14][15][16] We report here the synthesis of a few 2-substituted-6-hydroxy and 6-methoxybenzothiazoles from ethyl 6-hydroxybenzothiazole-2-carboxylate, in turn obtained from 1,4-benzoquinone.…”

Microwave Induced Facile One-Pot Access to Diverse 2-Cyanobenzothiazole-A Key Intermediate for the Synthesis of Firefly Luciferin

“…Reaction of compound 16 with KCN in DMSO afforded the nitrile 11 (Scheme 4). Conditions of formation of 2-chloro derivative 16 were improved using isoamyl nitrite and copper (II) chloride in polyethylene glycol 200 [26] as solvent and yields were improved to 56%. More recently, the Sand-Meyer reaction was carried out by direct introduction of cyanide with CuCN/KCN [27] and following this approach a 41% yield was obtained.…”