Home Cart Sign in  
HazMat Fee +

There will be a HazMat fee per item when shipping a dangerous goods. The HazMat fee will be charged to your UPS/DHL/FedEx collect account or added to the invoice unless the package is shipped via Ground service. Ship by air in Excepted Quantity (each bottle), which is up to 1g/1mL for class 6.1 packing group I or II, and up to 25g/25ml for all other HazMat items.

Type HazMat fee for 500 gram (Estimated)
Excepted Quantity USD 0.00
Limited Quantity USD 15-60
Inaccessible (Haz class 6.1), Domestic USD 80+
Inaccessible (Haz class 6.1), International USD 150+
Accessible (Haz class 3, 4, 5 or 8), Domestic USD 100+
Accessible (Haz class 3, 4, 5 or 8), International USD 200+
Chemical Structure| 106-53-6 Chemical Structure| 106-53-6
Chemical Structure| 106-53-6

4-Bromothiophenol

CAS No.: 106-53-6

4.5 *For Research Use Only !

Cat. No.: A711689 Purity: 98%

Change View

Size Price

US Stock

Global Stock

In Stock
5g łÇʶÊÊ Inquiry Inquiry
10g łÇ˶ÊÊ Inquiry Inquiry
25g łÇď¶ÊÊ Inquiry Inquiry
100g łÍď¶ÊÊ Inquiry Inquiry
500g łÇî˶ÊÊ Inquiry Inquiry

US Stock: ship in 0-1 business day
Global Stock: ship in 2 weeks

  • 5g

    łÇʶÊÊ

  • 10g

    łÇ˶ÊÊ

  • 25g

    łÇď¶ÊÊ

  • 100g

    łÍď¶ÊÊ

  • 500g

    łÇî˶ÊÊ

In Stock

- +

US Stock: ship in 0-1 business day
Global Stock: ship in 2 weeks

  • 1-2 Day Shipping
  • High Quality
  • Technical Support
Product Citations

Alternative Products

Product Details of [ 106-53-6 ]

CAS No. :106-53-6
Formula : C6H5BrS
M.W : 189.07
SMILES Code : SC1=CC=C(Br)C=C1
MDL No. :MFCD00004845
InChI Key :FTBCOQFMQSTCQQ-UHFFFAOYSA-N
Pubchem ID :66049

Safety of [ 106-53-6 ]

GHS Pictogram:
Signal Word:Danger
Hazard Statements:H315-H319-H335-H301+H311+H331
Precautionary Statements:P261-P264-P270-P271-P280-P302+P352-P301+P310-P304+P340-P305+P351+P338-P311-P330-P361+P364-P405-P403+P233-P501
Class:6.1
UN#:2811
Packing Group:

Computational Chemistry of [ 106-53-6 ] Show Less

Physicochemical Properties

Num. heavy atoms 8
Num. arom. heavy atoms 6
Fraction Csp3 0.0
Num. rotatable bonds 0
Num. H-bond acceptors 0.0
Num. H-bond donors 0.0
Molar Refractivity 41.39
TPSA ?

Topological Polar Surface Area: Calculated from
Ertl P. et al. 2000 J. Med. Chem.

38.8 Ų

Lipophilicity

Log Po/w (iLOGP)?

iLOGP: in-house physics-based method implemented from
Daina A et al. 2014 J. Chem. Inf. Model.

2.11
Log Po/w (XLOGP3)?

XLOGP3: Atomistic and knowledge-based method calculated by
XLOGP program, version 3.2.2, courtesy of CCBG, Shanghai Institute of Organic Chemistry

3.25
Log Po/w (WLOGP)?

WLOGP: Atomistic method implemented from
Wildman SA and Crippen GM. 1999 J. Chem. Inf. Model.

2.74
Log Po/w (MLOGP)?

MLOGP: Topological method implemented from
Moriguchi I. et al. 1992 Chem. Pharm. Bull.
Moriguchi I. et al. 1994 Chem. Pharm. Bull.
Lipinski PA. et al. 2001 Adv. Drug. Deliv. Rev.

3.31
Log Po/w (SILICOS-IT)?

SILICOS-IT: Hybrid fragmental/topological method calculated by
FILTER-IT program, version 1.0.2, courtesy of SILICOS-IT, http://www.silicos-it.com

2.86
Consensus Log Po/w?

Consensus Log Po/w: Average of all five predictions

2.85

Water Solubility

Log S (ESOL):?

ESOL: Topological method implemented from
Delaney JS. 2004 J. Chem. Inf. Model.

-3.61
Solubility 0.0459 mg/ml ; 0.000243 mol/l
Class?

Solubility class: Log S scale
Insoluble < -10 < Poorly < -6 < Moderately < -4 < Soluble < -2 Very < 0 < Highly

Soluble
Log S (Ali)?

Ali: Topological method implemented from
Ali J. et al. 2012 J. Chem. Inf. Model.

-3.74
Solubility 0.0345 mg/ml ; 0.000183 mol/l
Class?

Solubility class: Log S scale
Insoluble < -10 < Poorly < -6 < Moderately < -4 < Soluble < -2 Very < 0 < Highly

Soluble
Log S (SILICOS-IT)?

SILICOS-IT: Fragmental method calculated by
FILTER-IT program, version 1.0.2, courtesy of SILICOS-IT, http://www.silicos-it.com

-3.36
Solubility 0.0822 mg/ml ; 0.000435 mol/l
Class?

Solubility class: Log S scale
Insoluble < -10 < Poorly < -6 < Moderately < -4 < Soluble < -2 Very < 0 < Highly

Soluble

Pharmacokinetics

GI absorption?

Gatrointestinal absorption: according to the white of the BOILED-Egg

High
BBB permeant?

BBB permeation: according to the yolk of the BOILED-Egg

Yes
P-gp substrate?

P-glycoprotein substrate: SVM model built on 1033 molecules (training set)
and tested on 415 molecules (test set)
10-fold CV: ACC=0.72 / AUC=0.77
External: ACC=0.88 / AUC=0.94

No
CYP1A2 inhibitor?

Cytochrome P450 1A2 inhibitor: SVM model built on 9145 molecules (training set)
and tested on 3000 molecules (test set)
10-fold CV: ACC=0.83 / AUC=0.90
External: ACC=0.84 / AUC=0.91

Yes
CYP2C19 inhibitor?

Cytochrome P450 2C19 inhibitor: SVM model built on 9272 molecules (training set)
and tested on 3000 molecules (test set)
10-fold CV: ACC=0.80 / AUC=0.86
External: ACC=0.80 / AUC=0.87

No
CYP2C9 inhibitor?

Cytochrome P450 2C9 inhibitor: SVM model built on 5940 molecules (training set)
and tested on 2075 molecules (test set)
10-fold CV: ACC=0.78 / AUC=0.85
External: ACC=0.71 / AUC=0.81

Yes
CYP2D6 inhibitor?

Cytochrome P450 2D6 inhibitor: SVM model built on 3664 molecules (training set)
and tested on 1068 molecules (test set)
10-fold CV: ACC=0.79 / AUC=0.85
External: ACC=0.81 / AUC=0.87

No
CYP3A4 inhibitor?

Cytochrome P450 3A4 inhibitor: SVM model built on 7518 molecules (training set)
and tested on 2579 molecules (test set)
10-fold CV: ACC=0.77 / AUC=0.85
External: ACC=0.78 / AUC=0.86

No
Log Kp (skin permeation)?

Skin permeation: QSPR model implemented from
Potts RO and Guy RH. 1992 Pharm. Res.

-5.15 cm/s

Druglikeness

Lipinski?

Lipinski (Pfizer) filter: implemented from
Lipinski CA. et al. 2001 Adv. Drug Deliv. Rev.
MW ≤ 500
MLOGP ≤ 4.15
N or O ≤ 10
NH or OH ≤ 5

0.0
Ghose?

Ghose filter: implemented from
Ghose AK. et al. 1999 J. Comb. Chem.
160 ≤ MW ≤ 480
-0.4 ≤ WLOGP ≤ 5.6
40 ≤ MR ≤ 130
20 ≤ atoms ≤ 70

None
Veber?

Veber (GSK) filter: implemented from
Veber DF. et al. 2002 J. Med. Chem.
Rotatable bonds ≤ 10
TPSA ≤ 140

0.0
Egan?

Egan (Pharmacia) filter: implemented from
Egan WJ. et al. 2000 J. Med. Chem.
WLOGP ≤ 5.88
TPSA ≤ 131.6

0.0
Muegge?

Muegge (Bayer) filter: implemented from
Muegge I. et al. 2001 J. Med. Chem.
200 ≤ MW ≤ 600
-2 ≤ XLOGP ≤ 5
TPSA ≤ 150
Num. rings ≤ 7
Num. carbon > 4
Num. heteroatoms > 1
Num. rotatable bonds ≤ 15
H-bond acc. ≤ 10
H-bond don. ≤ 5

2.0
Bioavailability Score?

Abbott Bioavailability Score: Probability of F > 10% in rat
implemented from
Martin YC. 2005 J. Med. Chem.

0.55

Medicinal Chemistry

PAINS?

Pan Assay Interference Structures: implemented from
Baell JB. & Holloway GA. 2010 J. Med. Chem.

0.0 alert
Brenk?

Structural Alert: implemented from
Brenk R. et al. 2008 ChemMedChem

1.0 alert: heavy_metal
Leadlikeness?

Leadlikeness: implemented from
Teague SJ. 1999 Angew. Chem. Int. Ed.
250 ≤ MW ≤ 350
XLOGP ≤ 3.5
Num. rotatable bonds ≤ 7

No; 1 violation:MW<1.0
Synthetic accessibility?

Synthetic accessibility score: from 1 (very easy) to 10 (very difficult)
based on 1024 fragmental contributions (FP2) modulated by size and complexity penaties,
trained on 12'782'590 molecules and tested on 40 external molecules (r2 = 0.94)

1.22

Application In Synthesis of [ 106-53-6 ]

* All experimental methods are cited from the reference, please refer to the original source for details. We do not guarantee the accuracy of the content in the reference.

  • Downstream synthetic route of [ 106-53-6 ]

[ 106-53-6 ] Synthesis Path-Downstream   1~16

  • 1
  • [ 53595-65-6 ]
  • [ 106-53-6 ]
  • [ 63031-82-3 ]
  • 2
  • [ 74-96-4 ]
  • [ 106-53-6 ]
  • [ 30506-30-0 ]
YieldReaction ConditionsOperation in experiment
96% With triethylamine; In acetonitrile; for 17h;Reflux; [00144] A mixture of 4-bromobenzenethiol (50 g, 0.26 mol), bromoethane (58 g, 0.53 mol) and triethylamine (78 g, 0.78 mol) in acetonitrile (1 L) was stirred at reflux for 17 h. The mixture was cooled to rt and filtered. The filtrate was concentrated under vacuum. The residue was purified by silica gel chromatography (eluting with petroleum ether) to give (4- bromophenyl)(ethyl)sulfane (55 g, 96%) as an oil. 1H NMR (CDC13, 400 MHz): δ 7.40-7.42 (dd, J = 6.4, 2.0 Hz, 2H), 7.18-7.20 (dd, J = 6.4, 2.0 Hz, 2H), 2.91-2.96 (q, J = 1.2 Hz, 2H), 1.30-1.33 (t, J = 7.2 Hz, 3H).
96% With triethylamine; In acetonitrile; for 17h;Reflux; A mixture of 4-bromobenzenethiol (50 g, 0.26 mol), bromoethane (58 g, 0.53 mol) and triethylamine (78 g, 0.78 mol) in acetonitrile (1 L) was stirred at reflux for 17 h. The mixture was cooled to rt and filtered. The filtrate was concentrated under vacuum. The residue was purified by silica gel chromatography (eluting with petroleum ether) to give (4-bromophenyl)(ethyl)sulfane (55 g, 96%) as an oil. 1H NMR (CDCl3, 400 MHz): δ 7.40-7.42 (dd, J=6.4, 2.0 Hz, 2H), 7.18-7.20 (dd, J=6.4, 2.0 Hz, 2H), 2.91-2.96 (q, J=7.2 Hz, 2H), 1.30-1.33 (t, J=7.2 Hz, 3H).
96% With triethylamine; In acetonitrile; for 17h;Reflux; A mixture of 4-bromobenzenethiol (50 g, 0.26 mol), bromoethane (58 g, 0.53 mol) and triethylamine (78 g, 0.78 mol) in acetonitrile (1 E) was stirred at reflux for 17 h. The mixture was cooled to it and filtered. The filtrate was concentrated under vacuum. The residue was purified by silica gel chromatography (eluting with petroleum ether) to give (4-bromophenyl)(ethyl)sulfane (55 g, 96%) as an oil. ‘H NMR (CDC13, 400 MHz): ö 7.40-7.42 (dd, J=6.4, 2.0 Hz,2H), 7.18-7.20 (dd, J=6.4, 2.0 Hz, 2H), 2.91-2.96 (q, J=7.2 Hz, 2H), 1.30-1.33 (t, J=7.2 Hz, 3H).
96% With triethylamine; In acetonitrile; for 17h;Reflux; A mixture of 4-bromobenzenethiol (50 g, 0.26 mol), bromoethane (58 g, 0.53 mol) and triethylamine (78 g, 0.78 mol) in acetonitrile (1 L) was stirred at reflux for 17 h. The mixture was cooled to rt and filtered. The filtrate was concentrated under vacuum. The residue was purified by silica gel chromatography (eluting with petroleum ether) to give (4- bromophenyl)(ethyl)sulfane (55 g, 96%) as an oil. 1H NMR (CDC13, 400 IVIHz): 5 7.40-7.42 (dd, J 6.4, 2.0 Hz, 2H), 7.18-7.20 (dd, J 6.4, 2.0 Hz, 2H), 2.91-2.96 (q, J= 7.2 Hz, 2H), 1.30-1.33 (t, J 7.2 Hz, 3H).
96% With triethylamine; In acetonitrile; for 17h;Reflux; [00199] Step 1: (4-bromophenyl)(ethyl)sulfane [0987] [00200] A mixture of 4-bromobenzenethiol (50 g, 0.26 mol), bromoethane (58 g, 0.53 mol) and triethylamine (78 g, 0.78 mol) in acetonitrile (1 L) was stirred at reflux for 17 h. The mixture was cooled to rt and filtered. The filtrate was concentrated under vacuum. The residue was purified by silica gel chromatography (eluting with petroleum ether) to give (4- bromophenyl)(ethyl)sulfane (55 g, 96%) as an oil. 1H NMR (CDC13, 400 MHz): δ 7.40-7.42 (dd, J = 6.4, 2.0 Hz, 2H), 7.18-7.20 (dd, J = 6.4, 2.0 Hz, 2H), 2.91-2.96 (q, J = 7.2 Hz, 2H), 1.30- 1.33 (t, 7 = 7.2 Hz, 3H).

  • 3
  • [ 64-67-5 ]
  • [ 106-53-6 ]
  • [ 30506-30-0 ]
  • 4
  • [ 75-03-6 ]
  • [ 106-53-6 ]
  • [ 30506-30-0 ]
YieldReaction ConditionsOperation in experiment
93% With caesium carbonate; In N,N-dimethyl-formamide; at 20℃; for 12h; 4-Bromobenzenethiol (0.3g, 1.59 mmol, 1.0 equiv) was dissolved in N, N-dimethylformamide (6 mL). Cs2CO3 (1.55 g, 4.76 mmol, 3.0 equiv), lodoethane (0.15 mL, 1.9 mmol, 1.2 equiv) were added and the reaction mixture was stirred at room temperature for 12 hours. The reaction mixture was diluted with water and extracted with EtOAc. The organic layer was washed with brine, dried over sodium sulfate and concentrated to afford a crude residue. The crude residue was purified by silica gel column chromatography (0-5 % EtOAc/Hexane) to afford the desired product 5.18a (0.32 g, 93 % yield). 1H NMR (400 MHz, DMSO) 6 7.50 (d, J = 8.6 Hz, 2H), 7.26 (d, J = 8.6 Hz, 2H), 2.99 (q, J = 7.3 Hz, 2H), 1.23 (t, J = 7.3 Hz, 3H).
88% With sodium hydride; In N,N-dimethyl-formamide; mineral oil; at 20℃; for 18h; To a solution of 4-bromobenzenethiol (6, 0.35 g, 1.85 mmol) in DMF (2 mL) was added sodium hydride (0.111 g, 60% dispersion in mineral oil, 2.77 mmol) followed by iodoethane (0.58 g, 3.7 mmol) and the mixture stirred for 18 h at r.t. The reaction mixture was diluted with water (40 mL) and extracted with EtOAc (2 x 50 mL). The combined organic extracts were dried over MgSO4, filtered, and concentrated. Purification of the resultant residue by column chromatography (eluant 5% EtOAc in hexanes) provided the title compound (0.356 g, 88% yield) as a colorless oil. 1H NMR (400 MHz, CDCl3) ppm 1.28 (t, J = 7.5 Hz, 3H), 2.89 (q, J = 7.5 Hz, 2H), 7.11-7.19 (m, 2H), 7.33-7.40 (m, 2H).
  • 5
  • [ 106-53-6 ]
  • [ 145349-76-4 ]
  • 6
  • [ 76969-87-4 ]
  • [ 106-53-6 ]
  • [ 796072-28-1 ]
YieldReaction ConditionsOperation in experiment
100% With caesium carbonate; In DMF (N,N-dimethyl-formamide); at 0 - 20℃; for 2h; A solution of 4-bromobenzenethiol (670 mg, 3.55 mmol) and (L)-4-BROMO-2-TERT-BUTOXYCARBONYLAMINO-BUTYRIC acid methyl ester (1 g, 3.38 mmol) in DMF (15 mL) was cooled to 0 C and treated with CS2CO3 (1.2 g, 3.7 MMOL). Once the addition was complete, the reaction mixture was warmed to room temperature, stirred for 2 h, diluted with ethyl acetate (100 mL) and washed sucssevely with sat. aq NH4C1 and sat. aq NaCl. The resulting solution was dried over MGS04 concentrated and purified by flash column chromatography (10% ethyl acetate in heptane) to give 4- (4 -BROMOPHENYLSULFANYL)-2-TERT- Butoxycarbonylaminobutryic acid methyl ester (1.37g, 100 %) as SOLID. 1H NMR (CDC13), 6 7. 38 (d, J = 12 HZ, 2 H), 7.18 (d, J = 12 Hz, 2 H), 5.08 (d, J = 8 Hz, 1 H), 4.43 (m, 1 H), 3.73 (s, 3 H), 2.92 (m, 2 H), 2.21 (m, 2 H), 1.45 (s, 9 H).
  • 7
  • [ 76969-87-4 ]
  • [ 106-53-6 ]
  • 4-(4'-bromophenylsulfanyl)-2-tert-butoxycarbonylaminobutyric acid methyl ester [ No CAS ]
YieldReaction ConditionsOperation in experiment
100% With caesium carbonate; In N,N-dimethyl-formamide; at 0 - 20℃; for 2h; Example 121; 2-tert-Butoxycarbonylamino-4- (4' -dibenzofuan-4-yl-biphenyl~4~ ylsulfanyl) -butryic acid; 1. 4- (4' -bromophenylsulfanyl) -2-tert-Butoxycarbonylaminobutryic acid methyl ester; A solution of 4-bromobenzenethiol (670 mg, 3.55 mmol) and (L) -4-bromo-2-tert-butoxycarbonylamino-butyric acid methyl ester (1 g, 3.38 mmol) in DMF (15 mL) was cooled to 0 0C and treated with CS2CO3 (1.2 g, 3.7 mmol) . Once the addition was complete, the reaction mixture was warmed to room temperature, stirred for 2 h, diluted with ethyl acetate (100 mL) and EPO <DP n="204"/>washed sucssevely with sat. aq NH4Cl and sat. aq NaCl. The resulting solution was dried over MgSO4 concentrated and purified by flash column chromatography (10% ethyl acetate in heptane) to give 4- (4' -bromophenylsulfanyl) -2-tert- Butoxycarbonylaminobutryic acid methyl ester (1.37g, 100 %) as solid.
  • 8
  • [ 5424-47-5 ]
  • [ 106-53-6 ]
  • 3-(4-bromophenylsulphonyl)-1-(thiophen-2-yl)-1-propanone [ No CAS ]
  • 9
  • [ 5424-47-5 ]
  • [ 106-53-6 ]
  • [ 477859-21-5 ]
  • 10
  • [ 3032-81-3 ]
  • [ 106-53-6 ]
  • [ 1451093-06-3 ]
YieldReaction ConditionsOperation in experiment
With 2,2,6,6-tetramethylheptane-3,5-dione; caesium carbonate; copper(l) chloride; In 1-methyl-pyrrolidin-2-one; at 130℃; for 2h;Inert atmosphere; Sealed tube; N-Methyl-2-pyrrolidone (10 mL) was added to 4-bromothiophenol (0.500 g, 2.64 mmol) in a sealed tube and the mixture was purged with argon for 5 minutes. After this time, <strong>[3032-81-3]3,5-dichloroiodobenzene</strong> (0.72 g, 2.64 mmol), CuCl (0.131 g, 1.32 mmol), tetramethyl heptanedione (0.14 mL, 0.66 mmol) and cesium carbonate (1.70 g, 5.28 mmol) were added to the reaction mixture. The reaction mixture was stirred at 130° C. under argon for 2 hours. The reaction mixture was cooled to room temperature, diluted with ethyl acetate, and filtered through a celite bed. The filtrate was washed with water and brine, dried over anhydrous sodium sulfate and concentrated under reduced pressure to yield the crude product. Silica gel chromatography (neat hexanes) provided impure 1-(4-bromo-phenylsulfanyl)-3,5-dichloro-benzene (0.7 g). MS calcd. for C12H8BrCl2S [(M+H)+] 334, obsd. 334.
  • 11
  • [ 106-53-6 ]
  • [ 175278-00-9 ]
  • [ 1451092-99-1 ]
YieldReaction ConditionsOperation in experiment
With 2,2,6,6-tetramethylheptane-3,5-dione; caesium carbonate; copper(l) chloride; In 1-methyl-pyrrolidin-2-one; at 130℃; for 2h;Sealed tube; Inert atmosphere; N-Methyl-2-pyrrolidone (10 mL) was added to 4-bromothiophenol (0.500 g, 2.64 mmol) in a sealed tube and the mixture was purged with argon for 5 minutes. After this time, <strong>[175278-00-9]2-(trifluoromethoxy)iodobenzene</strong> (0.73 g, 2.53 mmol), CuCl (0.131 g, 1.32 mmol), tetramethyl heptanedione (0.14 mL, 0.66 mmol) and cesium carbonate (1.70 g, 5.28 mmol) were added to the reaction mixture. The reaction was stirred at 130 C. under argon for 2 hours. The reaction mixture was cooled to room temperature, diluted with ethyl acetate, and filtered through a celite bed. The filtrate was washed with water and brine, dried over anhydrous sodium sulfate and concentrated under reduced pressure to yield the crude product. Silica gel chromatography (neat hexanes) provided impure 1-bromo-4-(2-(trifluoromethoxy)phenylsulfanyl)benzene (0.72 g) as a solid.
  • 12
  • [ 106-53-6 ]
  • [ 2050-48-8 ]
  • 13
  • [ 20026-96-4 ]
  • [ 106-53-6 ]
  • C17H12BrClO2S [ No CAS ]
YieldReaction ConditionsOperation in experiment
78% With di-tert-butyl peroxide; iodine; at 110℃; for 18h;Inert atmosphere; Sealed tube; Schlenk technique; Green chemistry; General procedure: A 25 mL Schlenk tube equipped with a magnetic stirringbar was charged with I2 (12.7 mg, 0.05 mmol), substituted thiol1 (0.5 mmol) and alkyne 2 (0.75 mmol). The tube was evacuatedtwice and backfilled with nitrogen, and DTBP (2.5 mmol)was added into the tube under nitrogen atmosphere. The tubewas sealed with a balloon and the mixture was stirred undernitrogen atmosphere at 110 C for 18 h. Upon completion of thereaction, the resulting solution was cooled to r.t., and thesolvent was removed with the aid of a rotary evaporator. Theresidue was purified by column chromatography on silica gel(PE-EtOAc) to give 3.
  • 14
  • [ 106-53-6 ]
  • [ 546-43-0 ]
  • 3-(((4-bromophenyl)thio)methyl)-5,8a-dimethyl-3a,5,6,7,8,8a,9,9a-octahydronaphtho[2,3-b]furan-2(3H)-one [ No CAS ]
  • 15
  • [ 42182-27-4 ]
  • [ 106-53-6 ]
  • [ 536-74-3 ]
  • 2-((1-((4-bromophenyl)thio)-2-oxo-2-phenylethyl)amino)isonicotinonitrile [ No CAS ]
  • 16
  • [ 106-53-6 ]
  • ethyl halide [ No CAS ]
  • [ 30506-30-0 ]
 

Historical Records

Technical Information

Categories