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Smiles Rearrangement Phenothiazine Synthesis
Research Guide

What is Smiles Rearrangement Phenothiazine Synthesis?

Smiles rearrangement in phenothiazine synthesis is a nucleophilic aromatic substitution reaction where ortho-aminophenyl thioethers cyclize to form the tricyclic phenothiazine core under basic or halogen-induced conditions.

This method enables efficient construction of phenothiazine scaffolds from substituted 2-aminobenzenethiols or related precursors. Key papers include Mital and Jain (1969, 31 citations) on 5-substituted derivatives and Nodiff and Hausman (1964, 21 citations) on halogen-induced variants. Over 10 papers from the list detail optimizations and applications.

Curated Papers

Key Challenges

Why It Matters

Smiles rearrangement provides regioselective access to substituted phenothiazines for drug discovery, as in Gupta et al. (1993, 32 citations) for fluorinated anticancer agents and Sharma et al. (1999, 29 citations) for fluorophenothiazine sulfones. These routes support library synthesis mimicking antipsychotic and antimicrobial leads like chlorpromazine. Badshah and Naeem (2016, 100 citations) highlight thiazine derivatives' pharmacological potential from such methods.

Key Research Challenges

Regioselectivity Control

Achieving precise substitution patterns during cyclization remains difficult due to competing migration pathways. Mital and Jain (1969) addressed 5-substituted thiols but noted limitations with electron-withdrawing groups. Nodiff and Hausman (1964) used halogen induction to improve yields yet regioselectivity issues persist in polyfluorinated cases per Sharma et al. (1999).

Reaction Condition Optimization

Harsh bases or high temperatures degrade sensitive substituents like nitro or alkoxy groups. Gupta et al. (1993) optimized for fluorinated benzothiazines but yields varied. Recent reviews like Badshah and Naeem (2016) call for greener conditions to scale synthesis.

Substrate Scope Expansion

Limited to ortho-amino thioethers; extending to diazaphenothiazines or fused systems challenges yields. Morak-Młodawska et al. (2014, 32 citations) succeeded with 1,8-diazaphenothiazines but via alternative routes. Pluta and Morak-Młodawska (2009, 21 citations) note alkylation issues post-Smiles.

Essential Papers

Bioactive Thiazine and Benzothiazine Derivatives: Green Synthesis Methods and Their Medicinal Importance

Syed Lal Badshah, Abdul Naeem · 2016 · Molecules · 100 citations

Thiazines are a group of heterocyclic organic compounds that are still largely unexplored for their pharmacological activities. There are different available methods for the synthesis of thiazine d...

Synthetic and spectral investigation of fluorinated phenothiazines and 4H-1,4-benzothiazines as potent anticancer agents

R. Gupta, M. Jain, R.S. Rathore et al. · 1993 · Journal of Fluorine Chemistry · 32 citations

Synthesis and selected immunological properties of 10-substituted 1,8-diazaphenothiazines

Beata Morak‐Młodawska, Krystian Pluta, Michał Zimecki et al. · 2014 · Medicinal Chemistry Research · 32 citations

Synthesis of quinoline/naphthalene-containing azaphenothiazines and their potent in vitro antioxidant properties

Małgorzata Jeleń, Eugenia I. Bavavea, Μαρία Παππά et al. · 2014 · Medicinal Chemistry Research · 31 citations

Synthesis of some 5-substituted 2-aminobenzenethiols and their conversion into phenothiazines via Smiles rearrangement

R. L. Mital, Suresh Jain · 1969 · Journal of the Chemical Society C Organic · 31 citations

An improved and direct method for the preparation of 5-substituted 2-aminobenzenethiols (III; R = Cl, Br, Me, OMe, or NO2) through hydrolytic cleavage of substituted 2-aminobenzothiazoles (II; R = ...

Synthesis of fluorophenothiazines via Smiles rearrangement and their conversion into sulfones

Neerja Sharma, R. Gupta, M. Kumar et al. · 1999 · Journal of Fluorine Chemistry · 29 citations

Synthetic, biological and optoelectronic properties of phenoxazine and its derivatives: a state of the art review

Chandrita Sadhu, Amrit Krishna Mitra · 2023 · Molecular Diversity · 28 citations

Reading Guide

Foundational Papers

Start with Nodiff and Hausman (1964) for halogen-induced Smiles mechanism, then Mital and Jain (1969) for substituted thiol synthesis, followed by Sharma et al. (1999) and Gupta et al. (1993) for fluorinated extensions.

Recent Advances

Badshah and Naeem (2016) for green methods overview; Morak-Młodawska et al. (2014) for diazaphenothiazine applications and biological properties.

Core Methods

Core techniques: thiol preparation via benzothiazole hydrolysis (Mital 1969), base-promoted cyclization, halogen catalysis (Nodiff 1964), sulfone conversion (Sharma 1999).

How PapersFlow Helps You Research Smiles Rearrangement Phenothiazine Synthesis

Discover & Search

Research Agent uses searchPapers('Smiles rearrangement phenothiazine synthesis') to retrieve Mital and Jain (1969), then citationGraph to map 31 citing works and findSimilarPapers for fluorinated variants like Sharma et al. (1999). exaSearch uncovers green synthesis links from Badshah and Naeem (2016).

Analyze & Verify

Analysis Agent applies readPaperContent on Nodiff and Hausman (1964) to extract halogen conditions, verifyResponse with CoVe against Gupta et al. (1993) for yield comparisons, and runPythonAnalysis to plot reaction yields from extracted data using pandas/matplotlib. GRADE grading scores methodological rigor on 1-5 scale.

Synthesize & Write

Synthesis Agent detects gaps in substrate scope from Morak-Młodawska et al. (2014) papers, flags contradictions in fluorination yields. Writing Agent uses latexEditText for scheme editing, latexSyncCitations to integrate 10 papers, latexCompile for PDF, and exportMermaid for cyclization mechanism diagrams.

Use Cases

"Extract yield data from Smiles rearrangement papers and plot vs substituent type"

Research Agent → searchPapers → Analysis Agent → readPaperContent (Mital 1969, Sharma 1999) → runPythonAnalysis (pandas groupby substituents, matplotlib barplot) → researcher gets CSV/yield plot verifying optimal groups.

"Draft LaTeX reaction scheme for fluorophenothiazine synthesis via Smiles"

Research Agent → citationGraph (Gupta 1993) → Synthesis Agent → gap detection → Writing Agent → latexEditText (add scheme), latexSyncCitations (5 papers), latexCompile → researcher gets compiled PDF with cited mechanism.

"Find GitHub repos with Smiles rearrangement code for phenothiazine modeling"

Research Agent → exaSearch('Smiles phenothiazine') → Code Discovery → paperExtractUrls → paperFindGithubRepo → githubRepoInspect → researcher gets repo links with quantum chem scripts simulating Nodiff (1964) conditions.

Automated Workflows

Deep Research workflow scans 50+ phenothiazine papers via searchPapers, structures Smiles method evolution report citing Mital (1969) to Badshah (2016). DeepScan's 7-step chain verifies Gupta (1993) yields with CoVe checkpoints and runPythonAnalysis stats. Theorizer generates hypotheses on green Smiles variants from Badshah review gaps.

Try Doxa for Smiles Rearrangement Phenothiazine Synthesis Research

Frequently Asked Questions

What defines Smiles rearrangement in phenothiazine synthesis?

It is base- or halogen-promoted cyclization of ortho-aminophenyl thioethers to phenothiazines via intramolecular nucleophilic substitution, as introduced by Nodiff and Hausman (1964).

What are common methods in this subtopic?

Methods include hydrolytic thiol preparation (Mital and Jain, 1969), halogen-induced rearrangement (Nodiff and Hausman, 1964), and fluorinated substrate adaptations (Sharma et al., 1999; Gupta et al., 1993).

What are key papers?

Foundational: Mital and Jain (1969, 31 citations), Nodiff and Hausman (1964, 21 citations); recent: Badshah and Naeem (2016, 100 citations) reviews applications.

What open problems exist?

Challenges include regioselectivity in polysubstituted cases, greener conditions (Badshah and Naeem, 2016), and broader substrate scope beyond thiols (Morak-Młodawska et al., 2014).