1,5-Dibromo-3,3-dimethylpentane

• CAS: 37746-17-1
• Catalog Number: ACM37746171
• Category: Main Products
• Molecular Weight: 257.99
• Molecular Formula: C₇H₁₄Br₂
• Synonyms: 1,5-DIBROMO-3,3-DIMETHYLPENTANE
• IUPAC Name: 1,5-dibromo-3,3-dimethylpentane
• SMILES: CC(C)(CCBr)CCBr
• InChI Key: RITBDIOQNLAQSN-UHFFFAOYSA-N
• Exact Mass: 255.94600

Case Study

Study on the Synthesis and Application of 1,5-Dibromo-3,3-dimethylpentane in Heterocycle and Spirohydrocarbon Preparation

Schmerling, Louis, et al. The Journal of the American Chemical Society 74.11 (1952): 2885-2889

This study investigated the synthesis of 1,5-dibromo-3,3-dimethylpentane and its application in preparing heterocyclic compounds and spirohydrocarbons, using metal chloride-catalyzed condensation and nucleophilic substitution reactions. 1,5-dibromo-3,3-dimethylpentane was synthesized in 82% yield by adding hydrogen bromide to isoprene under 30 atm initial pressure at room temperature, with a boiling point of 54-55°C (4 mm) and refractive index
n
D
20

=1.5065
. The compound was used as a difunctional alkylating agent to react with various nucleophiles: reaction with ammonium hydroxide at 210°C yielded 4,4-dimethylpiperidine (19% yield) and 1,4,9,9-tetramethylbispiperidinium chloride (63% yield); reaction with sodium sulfide nonahydrate produced 4,4-dimethyltetrahydrothiopyran (73% yield). It also underwent N-alkylation with primary amines, forming 1-isopropyl-4,4-dimethylpiperidine (65% yield) and 1-phenyl-4,4-dimethylpiperidine (30% yield) with isopropylamine and aniline, respectively. Additionally, reaction with cyclopentadiene and sodium in liquid ammonia gave 8,8-dimethylspiro[4.5]-2,4-decadiene (23% yield), which was hydrogenated to 8,8-dimethylspiro[4.5]decane. These studies demonstrate that 1,5-dibromo-3,3-dimethylpentane is a versatile building block for synthesizing gem-dimethyl-containing heterocycles and spirohydrocarbons, with high reactivity in nucleophilic substitution and condensation reactions.
The in vitro synthesis and application of 1,5-dibromo-3,3-dimethylpentane were verified through controlled experiments. Synthesis was achieved by bubbling hydrogen bromide into isoprene under high pressure, followed by purification via distillation. For heterocycle preparation, 1,5-dibromo-3,3-dimethylpentane (0.1 mole) was mixed with nucleophiles (amines, sodium sulfide, etc.) and solvents (water, methylcyclohexane), heated in sealed tubes or autoclaves at 110-250°C for 4-16 hours. Spirohydrocarbon synthesis involved adding the dibromide dropwise to a solution of cyclopentadiene and sodium in liquid ammonia, followed by stirring, water quenching, and ether extraction. Products were purified by steam distillation, column chromatography, or recrystallization, and characterized by boiling point, refractive index, elemental analysis, and infrared spectroscopy. All reactions were performed under inert or controlled atmospheres to ensure product purity and yield.

Reaction of 1,5-Dibromo-3,3-dimethylpentane with tert-Butyllithium via Single-Electron-Transfer Mechanism

Bailey, William F., et al. Journal of Organic Chemistry 49.12 (1984): 2098-2107

This study investigated the reaction of 1,5-dibromo-3,3-dimethylpentane with tert-butyllithium (t-BuLi) in n-pentane-diethyl ether (3:2 by volume) at -23°C, focusing on product distribution and the underlying single-electron-transfer (SET) mechanism. 1,5-dibromo-3,3-dimethylpentane was synthesized following a reported procedure, with a purity confirmed by NMR and mass spectrometry. Reactions were conducted at varying substrate concentrations (0.001-0.1 M), and products were analyzed by GLC and GLC-MS. Results showed the reaction yielded a complex mixture: 1,1-dimethylcyclopentane (22-44% yield) from intramolecular cyclization, 3,3-dimethylpentane (24-32% yield) from formal reduction, and tert-butyl-containing alkanes (15-25% yield) from Wurtz-type coupling with t-BuLi. Higher dilution (0.001 M) minimized intermolecular dimerization but did not affect the extent of mixed coupling. The formation of cyclized products and radical-derived byproducts confirmed the reaction proceeds via SET, involving alkyl radical-halide ion adduct intermediates with halogen-dependent lifetimes. These studies demonstrate that 1,5-dibromo-3,3-dimethylpentane undergoes metal-halogen interchange and cyclization via SET, differing from analogous diiodides that afford clean cyclization.
The in vitro reaction of 1,5-dibromo-3,3-dimethylpentane with t-BuLi was verified through controlled experiments. A 0.1 M solution of the dibromide (10 mmol) in the solvent mixture was cooled to -23°C under argon, and 2.0-2.2 equiv of t-BuLi was added dropwise. The mixture was stirred for 30 minutes, quenched with water, and the organic phase was dried and analyzed. For concentration-dependent studies, substrate concentrations were adjusted to 0.01 M and 0.001 M. Product identities were confirmed by comparing retention times and mass spectra with authentic standards. Mechanistic probing using 6-bromo-1-hexene as a radical probe yielded methylcyclopentane, providing direct evidence for SET-mediated radical formation. Kinetic analysis and product distribution patterns supported the existence of alkyl radical-halide ion adducts, with bromide adducts having shorter lifetimes than iodide analogs, leading to competing cyclization, reduction, and coupling pathways.

Synthesis of 4,4-Dimethylthiane from 1,5-Dibromo-3,3-dimethylpentane via DMSO-Mediated Cyclization

Nagasawa, Kazuo, et al. Chemical & Pharmaceutical Bulletin 33.11 (1985): 5048-5052

This study developed a facile synthesis of 4,4-dimethylthiane using 1,5-dibromo-3,3-dimethylpentane as the precursor and dimethyl sulfoxide (DMSO) as the solvent, leveraging the gem-dimethyl effect for efficient cyclization. 1,5-dibromo-3,3-dimethylpentane was synthesized in three steps: reduction of 3,3-dimethylglutaric acid with lithium aluminum hydride to 3,3-dimethylpentane-1,5-diol (91% yield), bromination with phosphorus tribromide (77.5% yield), and purification by vacuum distillation. The cyclization reaction was conducted by mixing 1,5-dibromo-3,3-dimethylpentane (0.05 mol) with sodium sulfide nonahydrate (0.05 mol) in technical-grade DMSO, heating at 150°C for 20 minutes with vigorous stirring. The product 4,4-dimethylthiane was isolated by steam distillation and vacuum distillation, achieving a high yield of 92.3%. The product was characterized by boiling point (57-58°C/15 Torr), refractive index, and 1H NMR (0.95 ppm s, 6H; 1.60 ppm t, 4H; 2.65 ppm t, 4H). These studies demonstrate that DMSO is the optimal solvent for this cyclization, enabling short reaction times, minimal side products, and high yields due to the gem-dimethyl effect enhancing ring formation efficiency.
The in vitro synthesis and cyclization of 1,5-dibromo-3,3-dimethylpentane were verified through controlled experiments. Precursor synthesis involved sequential reduction and bromination steps, with each intermediate purified and characterized by boiling point and refractive index. Cyclization conditions were optimized by testing solvents (benzene-water, THF-water, DMF, DMSO) and temperatures, confirming DMSO at 150°C provided the highest yield (92.3%) compared to other solvents (30-68% yields). The reaction was scaled up tenfold without yield loss, demonstrating reproducibility. Product identity was confirmed by 1H NMR, elemental analysis via tosylsulfimide derivative, and comparison with spectral data. The gem-dimethyl effect was critical for efficient cyclization, as 4,4-dimethylthiane exhibited higher yield than unsubstituted thiane analogs, avoiding polymeric sulfide formation common in aqueous-alcoholic solvent systems.

Study on the Temperature Dependence of Chemical Shifts of 1,5-Dibromo-3,3-dimethylpentane

Lambert, Joseph B., et al. Journal of the American Chemical Society 103.21 (1981): 6398-6402

This study investigated the temperature dependence of 13C chemical shifts of 1,5-dibromo-3,3-dimethylpentane to assess its conformational behavior, using variable-temperature nuclear magnetic resonance (VT-NMR) spectroscopy. The compound was prepared via established synthetic routes and purified by distillation, with its structure confirmed by 1H NMR and mass spectrometry. VT-NMR spectra were recorded from 180 K to 300 K in a solvent mixture of 25% CDCl₃ and 70% CH₂Cl₂, with tetramethylsilane (Me4Si) as the internal reference. Results showed linear temperature gradients for all carbons except the quaternary C-3 (gem-dimethyl carbon), which exhibited a nonlinear response. The chemical shifts of methylene and methyl carbons moved upfield with decreasing temperature, with gradients ranging from positive values relative to uncorrected Me4Si. Correction for Me₄Si's inherent temperature dependence revealed downfield shifts at lower temperatures. However, calculated free energy differences from both corrected and uncorrected shifts showed no logical correlation with the expected conformational equilibrium (e.g., chair-twist forms), indicating that inherent factors (e.g., solution density changes) dominated the temperature dependence. These studies demonstrate that 13C chemical shift temperature gradients of 1,5-dibromo-3,3-dimethylpentane are primarily influenced by intrinsic effects rather than conformational equilibria, limiting the utility of this method for conformational analysis of such compounds.
The in vitro VT-NMR analysis of 1,5-dibromo-3,3-dimethylpentane was conducted using a Varian CFT-20 spectrometer operating at 20 MHz in pulsed Fourier transform mode with proton decoupling. Samples were prepared as 5% solutions in the solvent mixture, with a trace of Me4Si added for reference. Temperatures were calibrated using a thermocouple and maintained with a temperature-controlled probe. Chemical shifts were measured at intervals of 20 K, with 800-2000 scans accumulated per spectrum to ensure signal quality. Data analysis involved calculating temperature gradients via linear least-squares fitting and free energy differences assuming a two-conformer equilibrium. Internal shift comparisons (relative to C-5) were also performed to avoid reference standard artifacts. All experiments were replicated to confirm reproducibility, and results were compared with analogous compounds (e.g., 1,5-dibromopentane, 1,1-dimethylcyclohexane) to contextualize inherent effects.

Custom Q&A

What is the molecular formula of 1,5-Dibromo-3,3-dimethylpentane?

The molecular formula is C7H14Br2.

What are the synonyms for 1,5-Dibromo-3,3-dimethylpentane?

The synonyms are 1,5-DIBROMO-3,3-DIMETHYLPENTANE, 37746-17-1, SCHEMBL1976705, DTXSID50511272, and RITBDIOQNLAQSN-UHFFFAOYSA-N.

What is the molecular weight of 1,5-Dibromo-3,3-dimethylpentane?

The molecular weight is 257.99 g/mol.

When was 1,5-Dibromo-3,3-dimethylpentane created?

It was created on February 8, 2007.

When was 1,5-Dibromo-3,3-dimethylpentane last modified?

It was last modified on October 21, 2023.

What is the IUPAC name of 1,5-Dibromo-3,3-dimethylpentane?

The IUPAC name is 1,5-dibromo-3,3-dimethylpentane.

What is the InChI of 1,5-Dibromo-3,3-dimethylpentane?

The InChI is InChI=1S/C7H14Br2/c1-7(2,3-5-8)4-6-9/h3-6H2,1-2H3.

What is the InChIKey of 1,5-Dibromo-3,3-dimethylpentane?

The InChIKey is RITBDIOQNLAQSN-UHFFFAOYSA-N.

What is the canonical SMILES of 1,5-Dibromo-3,3-dimethylpentane?

The canonical SMILES is CC(C)(CCBr)CCBr.

What is the CAS number of 1,5-Dibromo-3,3-dimethylpentane?

The CAS number is 37746-17-1.