64784-13-0

Upstream product

• 120-72-9 indole 
• 480-93-3 indoxyl 
• 608-08-2 3-indoxyl acetate 
• 16433-96-8 2-ethynyl-1-nitrobenzene 
• 552-89-6 2-nitro-benzaldehyde 
• 67-64-1 acetone 
• 487-60-5 3-indoxyl-β-D-glucopyranoside 

Downstream Products

• 2903-89-1 dehydroindigo 
• 6537-68-4 leucoindigo 
• 861599-78-2 N,N-([2,2'-biindolinylidene]-3,3'-diylidene)bis(4-methylaniline) 
• 75863-33-1 indigo-N,N′-diphenyldiimine 
• 1253049-67-0 C₃₂H₂₈N₄ 
• 118-92-3 anthranilic acid 
• 483-20-5 indigo-5,5'-disulfonic acid 
• 894-86-0 leucoindigo 
• 1312089-99-8 2,2'-bis(indol-3-phenylimine) 
• 118-48-9 isatoic anhydride 
• 6268-38-8 N-methoxycarbonyl-anthranilic acid 
• 484-38-8 isatic acid 
• 40728-87-8 2,2'-bis(benzo-1,3-oxazinyl)-6,6'-dione 

Relevant academic research and scientific papers

Structural and Biochemical Studies Enlighten the Unspecific Peroxygenase from Hypoxylon sp. EC38 as an Efficient Oxidative Biocatalyst

Unspecific peroxygenases (UPOs) are glycosylated fungal enzymes that can selectively oxidize C-H bonds. UPOs employ hydrogen peroxide as the oxygen donor and reductant. With such an easy-to-handle cosubstrate and without the need for a reducing agent, UPOs are emerging as convenient oxidative biocatalysts. Here, an unspecific peroxygenase from Hypoxylon sp. EC38 (HspUPO) was identified in an activity-based screen of six putative peroxygenase enzymes that were heterologously expressed in Pichia pastoris. The enzyme was found to tolerate selected organic solvents such as acetonitrile and acetone. HspUPO is a versatile catalyst performing various reactions, such as the oxidation of prim- and sec-alcohols, epoxidations, and hydroxylations. Semipreparative biotransformations were demonstrated for the nonenantioselective oxidation of racemic 1-phenylethanol rac-1b (TON = 13 000), giving the product with 88% isolated yield, and the oxidation of indole 6a to give indigo 6b (TON = 2800) with 98% isolated yield. HspUPO features a compact and rigid three-dimensional conformation that wraps around the heme and defines a funnel-shaped tunnel that leads to the heme iron from the protein surface. The tunnel extends along a distance of about 12 ? with a fairly constant diameter in its innermost segment. Its surface comprises both hydrophobic and hydrophilic groups for dealing with substrates of variable polarities. The structural investigation of several protein-ligand complexes revealed that the active site of HspUPO is accessible to molecules of varying bulkiness with minimal or no conformational changes, explaining the relatively broad substrate scope of the enzyme. With its convenient expression system, robust operational properties, relatively small size, well-defined structural features, and diverse reaction scope, HspUPO is an exploitable candidate for peroxygenase-based biocatalysis.

CROSS-LINKING COMPOUNDS AND METHODS OF USE THEREOF

Compounds comprising a cross-linking moiety and a protecting group are described herein along with their methods of use. The cross-linking moiety may comprise an indoxyl and the protecting group may comprise a sugar (e.g., a glucuronide or glucoside), phosphoester, or sulfoester group. The cross-linking moiety and protecting group may be attached to each other via an oxygen atom, sulfur atom, or linker. In some embodiments, the linker attaching the cross-linking moiety and protecting group is a self-immolative linker. A compound of the present invention may cross-link under physiological conditions and/or in vivo.

CROSS-LINKING COMPOUNDS AND METHODS OF USE THEREOF

Compounds of Formula IA, IB, II, III, IV, and/or V are described herein along with their methods of use. A compound of the present invention may cross-link under physiological conditions and/or in vivo.

Indigo Formation and Rapid NADPH Consumption Provide Robust Prediction of Raspberry Ketone Synthesis by Engineered Cytochrome P450 BM3

Natural raspberry ketone has a high value in the flavor, fragrance and pharmaceutical industries. Its extraction is costly, justifying the search for biosynthetic routes. We hypothesized that cytochrome P450 BM3 (P450 BM3) could be engineered to catalyze the hydroxylation of 4-phenyl-2-butanone, a naturally sourceable precursor, to raspberry ketone. The synthesis of indigo by variants of P450 BM3 has previously served as a predictor of promiscuous oxidation reactions. To this end, we screened 53 active-site variants of P450 BM3 using orthogonal high-throughput workflows to identify the most streamlined route to all indigo-forming variants. Among the three known and 13 new indigo-forming variants, eight hydroxylated 4-phenyl-2-butanone to raspberry ketone. Previously unreported variant A82Q displayed the highest initial rates and coupling efficiencies in synthesis of indigo and of raspberry ketone. It produced the highest total concentration of raspberry ketone despite producing less total indigo than previously reported variants. Its productivity, although modest, clearly demonstrates the potential for development of a biocatalytic route to raspberry ketone. In addition to validating indigo as a robust predictor of this promiscuous activity, we demonstrate that monitoring rapid NADPH consumption serves as an alternative predictor of a promiscuous reactivity in P450 BM3.

Enzymatic synthesis of indigo-derivative industrial dyes

Synthetic indigo is among the most important industrial dyes. Unfortunately, synthetic indigo has raised environmental concern due to the use of pollutant and hazardous chemicals. In response, green chemistry aims to find new environmentally friendly and economically attractive synthesis methods. Accordingly, this work describes the enzymatic synthesis of indigo and its derivatives starting from indole. A variant of the heme domain of cytochrome P450 from Bacillus megaterium, CYPBM3F87A, was used to catalyze the synthesis of indigo and three di-substituted derivatives. Substrates transformed by a peroxygenase reaction were indole, 4-bromoindole, 5-methoxyindole and 7-methoxyindole. The kinetic data fitted to Hill's mathematical model with kcat values of 3.51, 0.94, 4.72, and 4.28 min?1 for each substrate, respectively. In all cases, colored products were obtained that were characterized by spectrometric techniques. Furthermore, the CYPBM3F87A enzyme was immobilized on magnetic nanoparticles that exhibited catalytic rate in the synthesis of indigo from indole (kcat 0.72 min?1). Our results show that enzymatic synthesis of industrial dyes without the use of expensive cofactors offers an attractive and plausible alternative to conventional chemical synthesis with a lower environment impact.

Exploring an anomaly: The synthesis of 7,7′-diazaindirubin through a 7-azaindoxyl intermediate

Two independent methods generating 7-azaindoxyl as an intermediate verify that 7,7′-diazaindirubin is formed exclusively over 7,7′-diazaindigo. This contrasts with long-standing knowledge related to the reactivity of indoxyl, which proceeds via a radical-initiated homodimerization process, leading to indigo. A series of experiments confirms 7-azaindoxyl as an intermediate with results suggesting a condensation pathway followed by oxidation.

Enzymatically triggered chromogenic cross-linking agents under physiological conditions

The ability to cross-link molecules upon enzymatic action under physiological conditions holds considerable promise for use in diverse life sciences applications. Here, an enzymatically triggered "click reaction" has been developed by exploiting the longstanding indigo-forming reaction from indoxyl β-glucoside. The covalent cross-linking proceeds in aqueous solution, requires the presence only of an oxidant (e.g., O2), and is readily detectable owing to the blue color of the resulting indigoid dye. To achieve facile indigoid formation in the presence of a bioconjugatable tether, diverse indoxyl β-glucosides were synthesized and studied in enzyme assays with four glucosidases including from tritosomes (derived from hepatic lysosomes) and rat liver homogenates. Altogether 36 new compounds (including 15 target indoxyl-glucosides for enzymatic studies) were prepared and fully characterized in pursuit of four essential requirements: enzyme triggering, facile subsequent indigoid dye formation, bioconjugatability, and synthetic accessibility. The 4,6-dibromo motif in a 5-alkoxy-substituted indoxyl-glucoside was a key design feature for fast and high-yielding indigoid dye formation. Two attractive molecular designs include (1) an indoxyl-glucoside linked to a bicyclo[6.1.0]nonyl (BCN) group for Cu-free click chemistry, and (2) a bis(indoxyl-glucoside). In both cases the linker between the reactive moieties is composed of two short PEG groups and a central triazine derivatized with a sulfobetaine moiety for water solubilization. Glucosidase treatment of the bis(indoxyl-glucoside) in aqueous solution gave oligomers that were characterized by absorption, dynamic light-scattering, and 1H NMR spectroscopy; optical microscopy; mass spectrometry; and HPLC. Key attractions of in situ indigoid dye formation, beyond enzymatic triggering under physiological conditions without exogenous catalysts or reagents, are the chromogenic readout and compatibility with attachment to diverse molecules.

Indigoid dyes by group e monooxygenases: Mechanism and biocatalysis

Since ancient times, people have been attracted by dyes and they were a symbol of power. Some of the oldest dyes are indigo and its derivative Tyrian purple, which were extracted from plants and snails, respectively. These 'indigoid dyes' were and still are used for coloration of textiles and as a food additive. Traditional Chinese medicine also knows indigoid dyes as pharmacologically active compounds and several studies support their effects. Further, they are interesting for future technologies like organic electronics. In these cases, especially the indigo derivatives are of interest but unfortunately hardly accessible by chemical synthesis. In recent decades, more and more enzymes have been discovered that are able to produce these indigoid dyes and therefore have gained attention from the scientific community. In this study, group E monooxygenases (styrene monooxygenase and indole monooxygenase) were used for the selective oxygenation of indole (derivatives). It was possible for the first time to show that the product of the enzymatic reaction is an epoxide. Further, we synthesized and extracted indigoid dyes and could show that there is only minor by-product formation (e.g. indirubin or isoindigo). Thus, group E monooxygenase can be an alternative biocatalyst for the biosynthesis of indigoid dyes.

High-Performance Ambipolar Polymers Based on Electron-Withdrawing Group Substituted Bay-Annulated Indigo

For donor–acceptor conjugated polymers, it is an effective strategy to improve their electron mobilities by introducing electron-withdrawing groups (EWGs, such as F, Cl, or CF3) into the polymer backbone. However, the introduction of different EWGs always requires a different synthetic approach, leading to additional arduous work. Here, an effective two-step method is developed to obtain EWG substituted bay-annulated indigo (BAI) units. This method is effective to introduce various EWGs (F, Cl, or CF3) into BAI at different substituted positions. Based on this method, EWG substituted BAI acceptors, including 2FBAI, 2ClBAI, and 2CF3BAI, are reported for the first time. Furthermore, four polymers of PBAI-V, P2FBAI-V, P2ClBAI-V, and P4OBAI-V are developed. All the polymers show ambipolar transport properties. Particularly, P2ClBAI-V exhibits remarkable hole and electron mobilities of 4.04 and 1.46 cm2 V?1 s?1, respectively. These mobilities are among the highest values for BAI-based polymers.

Green and efficient biosynthesis of indigo from indole by engineered myoglobins

With the demand nowadays for blue dyes, it is of practical importance to develop a green and efficient biocatalyst for the production of indigo. The design of artificial enzymes has been shown to be attractive in recent years. In a previous study, we engineered a single mutant of sperm whale myoglobin, F43Y Mb, with a novel Tyr-heme cross-link. In this study, we found that it can efficiently catalyze the oxidation of indole to indigo, with a yield as high as 54% compared to the highest yield (～20%) reported to date in the literature. By further modifying the heme active site, we engineered a double mutant of F43Y/H64D Mb, which exhibited the highest catalytic efficiency (198 M?1 s?1) among the artificial enzymes designed in Mb. Moreover, both F43Y Mb and F43Y/H64D Mb were found to produce the indigo product with a chemoselectivity as high as ～80%. Based on the reaction system, we also established a convenient and green dyeing method by dyeing a cotton textile during the biosynthesis of indigo, followed by further spraying the concentrated indigo, without the need of strong acids/bases or any reducing agents. The successful application of dyeing a white cotton textile with a blue color further indicates that the designed enzyme and the dyeing method have practical applications in the future.